Roger Federer, champion of 19 Grand Slams and arguably the greatest player of all time, is afraid of dogs. Wilson treated the Swiss to playtime with a group of dogs of all sizes for his 36th birthday back in August.

"I'm a little bit scared of dogs to be honest," Federer said.

Gracious as always, he embraced the moment and played with all of the dogs, even sharing a tale of his dolphin-feeding adventure in Brisbane.

"I love dogs, at the end of the day I do," Federer said. "I just haven't spent enough time with them. We always used to have a cat."