Carrie Underwood Not Dating Swimmer Michael Phelps 11/4/08

Country star Carrie Underwood has dismissed reports she's dating Olympic hero Michael Phelps.

The Before He Cheats singer, who previously dated Jessica Simpson's boyfriend Tony Romo, insists there's no truth in the latest romance reports. She tells Elle magazine, "I swear on everything, on my job, on my house, my dog…That's how serious I am. It's all just a lie."

And she's also addressing reports she still chats to her ex, Romo, over the phone: "It was just something that was said in passing, and I would never mean to say anything to hurt anybody or to stir up anything, because I'm just not about drama."

"I might be mad too if somebody said my boyfriend was calling some other girl. So I can definitely see where (Jessica) would be coming from. But I haven't talked to him since, like, May."