Watch Pregnant Ashlee Simpson Perform on Leno

Mom-to-be Ashlee Simpson performed her new single, "Little Miss Obsessive," on The Tonight Show With Jay Leno . She did not mention her plans to wed rocker Pete Wentz or Usmagazine.com 's exclusive report that she is expecting . Her new album, Bittersweet World (out today), was met with mixed reviews. The Washington Post said the tracks were "very, very empty," while the Dallas Morning News called Simpson "more listenable than ever." ( Us Weekly said the CD "shows that right now, the girl's just after a good time.") Click here for more photos of Simpson's burgeoning bump. Tell Us : Do you like Ashlee's performance? (link)