Turin, Italy - How this cat reacts to a portrait of his late best friend, a dog, has the internet crying. The heartbreaking TikTok clip has a whopping 25 million views!

Cleo was an old dog when her owners decided to get a kitten, and they named the rambunctious tabby Groot.

After a few weeks of spats and growing pains, the two became fast friends.

Cleo enjoyed the cat's attention and tolerated being pawed in the face, and Groot even liked to take naps and cuddle with Cleo.

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Unfortunately, their time together only lasted ten months because the eleven-year-old soon got sick and passed away.

After the dog's death, Cleo and Groot's owner, Asya Cutrino, hung a huge portrait of her beloved pooch in the living room.

But it wasn't just the humans in the family who noticed the new picture. Groot's reaction to his best friend's pic was striking, and Cutrion caught it on camera.

As the now super viral video shows, at first, the cat sits reverently in front of Cleo's portrait.

Then Groot stands up on his hind legs, leans on the photo, and gently strokes the dog's ear. The next frame shows the cat doing almost exactly the same thing with Cleo when he was alive.

Per Groot's owner, the touching gesture wasn't a one-off, the cat gives the pic of his old friend a sweet pet whenver the mood strikes.

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"Me and my whole family cried a lot when he did it," Cutrino told The Dodo.

TikTok was stunned by the cat's sweet gesture, and the video boasts over 25 million views and over five million likes.

Some time has passed since Cleo's death, but that Groot still gives the dog's pic little greetings.

"Every now and then, he stops by the portrait. I'm sure he remembers her," Cutrino said. "When I watch old videos of Cleo, and she's barking, Groot immediately runs to see if she is there."