“We got him from a shelter five years ago, at the age of 8,” Shannon Richardson, Sunny’s mom, told The Dodo. “He spent six years of his life looking for a new home and as soon as we met him, we had to adopt him!”

Sunny was perfectly happy with his life and routine — and then one day, his parents brought home a new human little sister named Hazel, and Sunny was immediately unimpressed.

“When we first brought Hazel home, he did not care for her much,” Richardson said. “We put the infant carrier down and he sniffed her, then walked away and went and ate his dinner.”

Sunny spent many months trying to make it clear that he wasn’t a fan of Hazel. His parents wondered if the stubborn cat would ever warm up to his new sister, until recently, when they happened to glance at the baby monitor and were shocked by what they saw.

After they put Hazel to bed one night, Sunny snuck into her room and jumped up into her crib — then curled up next to her and went to sleep.

“This was his first nap with her,” Richardson said. “I was super surprised to see him in the crib. There is not an easy way up without jumping pretty far and he doesn’t really like jumping. He stayed there for four hours before my husband realized he didn’t sneak back into bed with us!”

As it turns out, Sunny had always had a soft spot for Hazel — he just hadn’t been ready to show it yet.

Now that his secret is out, Sunny has no problem showing the world how much he loves Hazel. He follows her around whenever she’s crying, trying to make sure she’s OK, and loves to snuggle up to her every chance he gets.

“He actually jumped in her crib this morning when she was crying and nuzzled against her,” Richardson said. “She has not exactly gotten the hang of petting, so she grabbed him and he just stayed there. He is such a good boy.”

They may have had a bumpy start, but Sunny and Hazel are now on track to be best friends, and there’s no doubt that Sunny will be by her side for many naps to come.