Meghan Markle is mourning the loss of her beloved rescue beagle, Guy.

On Tuesday, Jan. 7, the Duchess of Sussex, 43, shared the news of her dog’s death on her new Instagram account, writing, in part: “I have cried too many tears to count – the type of tears that make you get in the shower with the absurd hope that the running water on your face will somehow make you not feel them, or pretend they’re not there. But they are. And that’s okay too. Thank you for so many years of unconditional love, my sweet Guy. You filled my life in ways you’ll never know. As ever, Meghan.”

Guy has been a constant presence through many of Meghan’s milestone moments — from her Suits days to Harry’s garden proposal and even her royal wedding day. He also made a cameo in the trailer for the duchess’s upcoming lifestyle series, With Love, Meghan, lounging comfortably in his dog bed beside her in the kitchen.

In her emotional tribute on Instagram, which was accompanied by a compilation of family photos and videos of Guy through the years (including sweet moments with her children, Prince Archie, 5, and Princess Lilibet, 3), Meghan shared: “In 2015, I adopted a beagle from a dog rescue in Canada. He had been at a kill shelter in Kentucky and given a few days to live. I swooped him up….and fell in love.

“They referred to him as ‘the little guy’ because he was so small and frail, so I named him ‘Guy’. And he was the best guy any girl could have asked for.

“If you followed me on instagram back in the day, you saw a lot of him – and on The Tig too. He was with me at Suits, when I got engaged, (and then married), when I became a mom….he was with me for everything: the quiet, the chaos, the calm, the comfort.

“He endured a terrible accident shortly before I moved to the UK which had him undergoing surgeries for several months and unable to leave the clinic. Doctors said he would never walk again, but Dr Noel Fitzpatrick said he could do it. H and I would drive late at night, after hours, to see Guy as he recovered in Surrey for months on end.

“I will always be grateful to Noel and his team, the team at Queen West Animal Hospital in TO, our vets now, and my friends and community: Thank you for loving him so.

“Because many of you will now see Guy in this new series, I hope you’ll come to understand why I am so devastated by his loss. I think you may fall a little bit in love too.”

Meghan Markle and her dog, Guy. Meghan Markle/Instagram

Guy had a fairytale rescue story that began in the Montgomery County Animal Shelter, a kill shelter in Mt. Sterling, Kentucky. Volunteers transported him to Ontario, Canada’s A Dog’s Dream Rescue in 2015, and shortly after his arrival, Meghan, 43, emailed the rescue center after finding its page on Petfinder. She thought a beagle — a breed known for being energetic, kind and gentle — would be a good match for her, and Dolores Doherty, the founder and owner of A Dog’s Dream Rescue, agreed, emailing Meghan an adoption application to fill out. She returned the completed application just 10 minutes later.

Doherty invited Meghan — who hadn’t yet met Prince Harry, 40 — to an upcoming adoption event at a local pet store, and Meghan showed up. Though Doherty didn’t know who Meghan was at the time (Meghan was a working actress, starring in the television show Suits at the time), she said she was struck by her sense of self, politeness and “her beauty really stood out,” she previously told PEOPLE.

Shortly after arriving at the event, Meghan zeroed in on Guy, quickly becoming smitten with the rescue dog after going on a trial walk with him. Meghan adopted him, and Guy quickly became a fixture on Meghan’s previous Instagram account, which she deleted in 2018 before marrying into the royal family.

Meghan Markle and her dogs. Meghan Markle/Instagram

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“This dog has a charmed life,” Doherty said she remembered thinking to herself after seeing the photos of Meghan and the sweet beagle with “magnificent ears and eyes.”

Of Meghan choosing to adopt, “It’s just wonderful, the exposure she created,” Doherty added. “She could’ve bought a dog, but she chose to adopt.”

Eventually, when Meghan moved to the U.K. to start her life with Prince Harry there, Guy joined her. In 2017, Guy suffered a setback when he broke two legs, which left Meghan “distraught” and “very upset.” Under the care of renowned veterinary surgeon Noel Fitzpatrick, Guy was nursed back to health, and when Harry and Meghan announced their engagement that November, he had a brief mention in their engagement interview when Meghan said, “Well, I have two dogs that I’ve had for quite a long time, both my rescue pups. And one is now staying with very close friends and my other little guy is — yes, he’s in the U.K., he’s been here for a while.”

Meghan, Harry and Guy, as seen in ‘Harry & Meghan’ on Netflix. Netflix

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The other dog, Bogart, was brought home by Meghan thanks to a nudge from none other than Ellen DeGeneres. Meghan once told Best Health that she was in a dog shelter when DeGeneres and her wife Portia de Rossi came in. DeGeneres asked Meghan if Bogart, a German Shepherd-Lab mix, was her dog, and Meghan said she was deciding whether to adopt him or not. After DeGeneres said, “Rescue the dog!” Meghan said, “It’s sort of like if Oprah tells you to do something. I’m sitting there holding him and she’s like, ‘Have you thought of a name for him yet?’ And I said, ‘Well, I think I’d name him Bogart,’ and she’s like, ‘You’re taking the dog home.’ ”

“And she walks outside to get into her car, but instead of getting in she turns around and comes and taps on the window glass and she yells, ‘Take the dog!’ And so I brought him home. Because Ellen told me to,” Meghan added.

Meghan Markle and Ellen DeGeneres. Karwai Tang/WireImage; Jon Kopaloff/FilmMagic

Ahead of her royal wedding to Prince Harry in May 2018, Guy even had a book released about his fairytale story called His Royal Dogness, Guy the Beagle: The Rebarkable True Story of Meghan Markle’s Rescue Dog. On her wedding day, Guy sat at Meghan’s feet as she had her hair and makeup done.

Meghan’s love of dogs was not only a point of attraction as she and Prince Harry were falling in love, but it charmed Queen Elizabeth, too. During their engagement interview, Harry revealed Meghan had charmed the Queen — and her corgis! — saying that “The corgis took to her straight away. I’ve spent the last 33 years being barked at — this one walks in, absolutely nothing.”

Meghan replied, “They were laying on my feet during tea!”

“Just wagging tails — and I was just like, argh,” Harry said in response.

Harry also wrote in his 2023 memoir Spare that “fur babies” were one of the topics he and Meghan bonded with King Charles and Queen Camilla over the first time she met them in 2016, the same year she and Harry met and began their relationship.

Prince Charles, Prince of Wales (L) and his wife Camilla, Duchess of Cornwall (C), and Meghan, Duchess of Sussex, listen as her husband Prince Harry, Duke of Sussex (unseen), speaks during the Prince of Wales’s 70th Birthday Garden Party at Buckingham Palace in London on May 22, 2018. DOMINIC LIPINSKI/AFP via Getty Images

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In 2018, Harry and Meghan adopted a black Labrador named Pula, which means “rain” in Setswana, the official language of Botswana, where Harry and Meghan had their third date.

In 2022, the couple — now parents to Archie and Lilibet and living in Montecito — adopted a senior rescue beagle named Mamma Mia, rescued from a Virginia breeding facility by the Beagle Freedom Project. Guy, Pula and Mamma Mia all were shown in Harry and Meghan’s 2024 holiday card — a first for Mamma Mia, as Guy and Pula had been depicted in previous holiday cards, as well.

“The Duke and Duchess of Sussex are the most loving, sensitive and caring adopters I have ever met!” animal rights attorney Shannon Keith, who runs the Beagle Freedom Project, told PEOPLE. “We were so honored that they have been supporting Beagle Freedom Project and chose to adopt a dog who has been abused.”

Keith added that Harry and Meghan could have taken one of the many puppies available, but they opted to adopt a senior dog.

Momma Mia, a beagle rescued by Prince Harry and Meghan Markle. Beagle Freedom Project/Mega

“They made a point to adopt a rescue named Mia, who most would overlook because she is older, has health issues and is traumatized by her past,” Keith said. “I was so impressed by their commitment to animal welfare! They have been following up letting us know how well Momma Mia is doing in her new, amazing home!”

During her time as a working royal, one of Meghan’s patronages was animal shelter and charity Mayhew, and she candidly wrote about being a rescue dog owner in the organization’s 2019 annual report. 

“As a proud rescue dog owner, I know from personal experience the joy that adopting an animal into your home can bring,” she wrote.

Meghan, Duchess of Sussex, during a forum about digital responsibility at EAN University during a visit around Colombia on Aug. 15, 2024 in Bogota, Colombia. Diego Cuevas/Getty Images

During a visit to Mayhew in January 2019, Meghan — who was “very natural with the dogs, as one needs to be,” CEO Caroline Yates said — told an anecdote about Guy, who was previously mistreated and left to roam wild.

“He was petrified to come in the front door. He didn’t know how to go up and down stairs,” Meghan said. “All the things you’re patient with and then you end up with the best dog in the world.”

During a difficult year where Harry and Meghan stepped back as working royals, relocated to the U.S. and suffered a pregnancy loss, Yates said Meghan’s dogs had been a source of “support” for the Duchess of Sussex.

“Whenever we talk to the Duchess about the charity, she always references how important her dogs are and what a support they are, particularly during everything that’s happened this year, with COVID, and with the personal trials and tribulations she went through this year,” Yates said about Meghan’s 2020.

“It was really nice to share our experiences with her about how important animals are when things are tough and what a comfort they can be,” she added.