A golden retriever named Clara and her feline brother, Cow, have melted hearts all over social media with their unexpectedly close friendship.

In a video posted on TikTok earlier in July by @goldensdigger, 29-year-old Yunah Choi shares the evolution of her pets' friendship from the day she brought the new kitten home.

Initially, Clara seemed confused about what to do with her new brother, but she immediately took a liking to the kitten. Now, they're best friends.

"My golden retriever was always there when my kitty was sick and now he is all recovered and they are absolute best friends!" the video's caption reads.

Choi told Newsweek that when she first brought Cow home, he was a foster cat battling a severe upper respiratory infection. This made him extremely fragile and in need of a lot of care.

"Our Golden Retriever, Clara, had never been around a cat before, and we weren't sure how she'd react. To our surprise, Clara immediately showed a gentle curiosity toward Cow. She seemed to understand that he was sick and needed extra love. Clara first was unsure how to react to a kitten but she figured it out eventually," Choi said.

"As Cow started to feel better, a beautiful friendship blossomed between them. Clara, with her patient and nurturing nature, taught Cow how to play and be a part of our family. They'd chase each other around the house, cuddle up together for naps, and share moments that melted our hearts daily."

What started as a temporary foster situation turned into a forever home for Cow, and now he and his big sister are the best of friends.

"Their bond has brought so much joy and warmth into our lives, and we're grateful every day for our furry family," Choi said.

Even though we all grew up believing that cats and dogs were mortal enemies, when introduced properly, they can live together peacefully and even become the best of friends.

A study carried out by Italian researchers and published in the journal PLOS ONE found that more than 62 percent of the cats and dogs involved in the survey that lived together also played together; 58 percent chased each other, and 41 percent fought. Almost two-thirds of the pets sometimes playfully "made ambushes" toward the other.

Choi's video quickly went viral on TikTok. It has so far received over 845,600 views and 30,300 likes on the platform.

One user, @Betsyboop500, commented: "Oh my heart when she ran up on day one then that little meow."

Commenter @Rachelannette77 wrote: "The sweetest thing I have seen on TikTok all day!"

Do you have funny and adorable videos or pictures of your pet you want to share? Send them to life@newsweek.com with some details about your best friend and they could appear in our Pet of the Week lineup.