11/03/2008 at 04:00 PM EST
has a message for Jessica Simpson
: She and ex Tony Romo have not spoken in months.
"I haven't talked to him since, like, May," Underwood, 25, tells Elle
in its December issue.
"It was just something that was said in passing," the country singer says, referring to an interview in which she said Romo still called her. "I would never mean to say anything to hurt anybody or to stir up anything because I'm just not about drama – at all."
As for reports that Simpson was upset by the claims, Underwood says, "I might be mad too if somebody said my boyfriend was calling some other girl. So I can definitely see where [she] would be coming from."
Asked about her current dating life, Underwood emphatically shoots down rumors that she dated Olympian Michael Phelps. "I swear on everything, on my job, on my house, my dog," she says. "That's how serious I am. It's all just a lie."
While Underwood has been linked to
Travis Stork, a former Bachelor
, the singer says she is not one to kiss and tell.
"If I say I am [dating someone] or I'm not, as soon as this magazine comes out, it might be the opposite of what I tell you now. In three months, it'll be 'Carrie said she's not dating anybody,' yet last night, I was out on the town with some guy. He's going to get mad at me. Everybody's going to think I'm a liar. It's just best not to go there."
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