Caroline Wozniacki says she helped motivate her boyfriend, top golfer Rory McIlroy, to get fit. Wozniacki said that the first time they went running together in Monaco, where she lives, McIlroy had to bail out.

“He didn't make it,” she said with a laugh. “It was so funny. We went out running. I have this round that I always do, but I was like, 'Oh, we're going to go to the gym afterwards,' so I was like, 'Let's just run, make this little loop—it takes maybe 25 minutes or something to make that—and then let's run up to the country club and then we go to the gym and we can run back home'. Perfect. Sounded like a great idea.

"But it was quite hot out there. After 15 minutes I could really see, he was struggling. So we had made half of the loop, and I was like, ‘You know what? If you want you can run up to the gym. I will finish my round and then I will run up to the gym.' [He said] ‘Yeah, yeah, let's do that. That sounds like a good idea.’"

The Dane added McIlroy has since become a fitness freak, and that he can now keep up with her.

"Now we go running all the time,” she said. "There's absolutely no problem. He loves the gym, loves to work out. He goes at least once a day, if not twice. He's in unbelievable shape.”