Ashlee Simpson ASimpson070408_01_X17.jpg Archive photo

Ashlee Simpson and Pete Wentz have been playing awfully coy when it comes to the gender of their looming baby - until now!

Pete's A Sewin' Celeb
The Star reports that Ashlee and Pete's first child will be a girl - and that the couple couldn't be happier about the news. "Ashlee and Pete are on cloud nine," an insider tells the mag.

Pete, in particular, appears to be thrilled - the Star claims that the rocker is even learning how to sew baby clothes in preparation for his daughter's arrival!

Trick or Treat?
And in a truly apt coincidence, Ashlee and Pete might be receiving their bundle of joy on

"The doctor told them they actually conceived the baby just before Valentine's Day while they were on vacation and has given them an initial due date of Oct. 31st," the Sun's source says. "When Pete heard he might have his baby on Halloween, he went nuts. For an emo-rocker type like Pete, that would be just too perfect!"

Hey, we're confident that Pete and Ashlee's daughter will be a treat - no matter when she shows up!