Hilary Duff's lips are sealed when it comes to ex-boyfriend Aaron Carter. While he's been going on and on about how much he regrets his split from the Lizzie McGuire alum, she has yet to respond to his proclamations of love -- and it sounds like she has no plans to do so anytime soon.

Asked about Carter's recent romantic revelations while attending the iHeartRadio Music Awards at L.A.'s Shrine Auditorium on May 1, the newly separated singer-actress replied, "I don't have an answer to that." (She and the former teen idol dated for three years before breaking up in 2003 amid rumors that he cheated on her with fellow Disney princess Lindsay Lohan.)

Fortunately, Carter isn't looking for answer. "[My tweets weren't] meant for the media or anybody like that -- I didn't think about it, really," he told Entertainment Tonight last month. "I wasn't really looking for [a response] either. I'm sure she got the message.