Christina Aguilera Welcomes Pete Wentz, Ashlee Simpson Into The Ranks Of Hollywood Parents

'They're about to be on the ride of their life,' singer says after her whirlwind medley at the American Music Awards.

[artist id="509026"]Christina Aguilera[/artist] gave birth to her first son, Max, in January, and she just popped out a new CD two weeks ago, so she can be forgiven for missing the news of the latest additions to the ranks of pop star parents, Pete Wentz and Ashlee Simpson.

"Oh, did they give birth? Oh, how exciting! Congratulations," she told MTV News on Sunday, after her performance at the American Music Awards. "I give my best. They're about to be on the ride of their life. It's just the most amazing thing you could ever experience."

At the awards show, Aguilera did a remix of some of her classics in honor of her new greatest-hits album, Keeps Gettin' Better — A Decade of Hits, which was released earlier this month exclusively at Target. "[The performance was a] seven-minute medley based on seven of my greatest hits, which was jam-packed and full of vigor and life and a lot of momentum and a lot of stamina ... but it was really, really fun going through 10 years in seven minutes."

Aguilera said she couldn't believe the album debuted at #9, considering that everyone has already heard most of the songs on it. "Well this is the last 10 years in the making," she said. "[I'm] very excited about the fact that it' even in the top ten being that these are songs that have already been hits and recreations of those hits."

She added, "So I'm in the studio currently working on my new album of all-new material, but this one in part is a fun thank you from me to the fans for helping me build such an amazing career."