Hilary Duff insists she did not knowingly reject Charli XCX's "Boom Clap." It is actually her "favorite song on the radio."

Imagine the regret associated with knowing that you chose not to record and release “Boom Clap,” which is now pop radio’s fastest-rising song.

Imagine the heartbreak associated with finding out that you could have been the one to record the track.

For the past month, music diehards assumed Hilary Duff fell into the former bucket. In a June interview with MTV UK, Charli XCX revealed that she and her co-writer Patrick Berger (with whom Duff has also worked) offered “Boom Clap” to the actress-singer.

“We sent over ‘Boom Clap,’ but [Duff’s team] came back and were like, ‘this isn’t cool enough for Hilary,'” explained Charli XCX. “I thought I was a cool writer, but maybe I’m not. Hilary didn’t want my song. What a life-ruiner.”

In a new interview with Pop Justice, Duff, however, suggests that she never knew she had the option to record and release “Boom Clap.”

“I didn’t know that I had an option to have it,” says Duff. “It’s my favorite song on the radio right now.

“I remember there was talk about my label trying to get us to write together, [but] it was in New York and I was flying home so I didn’t have time to have a session with her. I am literally obsessed with that song and I didn’t know that it was an option for me.”

#9 at pop radio and #14 on the Hot 100, “Boom Clap” has become a breakthrough solo hit for Charli XCX. She previously charted as a featured artist on Icona Pop’s “I Love It” and Iggy Azalea’s “Fancy.”

Duff, meanwhile, is on the verge of releasing comeback single “Chasing the Sun.” It was co-written by Colbie Caillat, Jason Reeves and Toby Gad and produced by Gad.