By peoplestaff225
Updated August 05, 2008 01:00 PM

Not one to let pregnancy slow her down, singer Ashlee Simpson-Wentz, 23, trekked to Chicago with husband Pete Wentz to enjoy the Lollapalooza music festival over the weekend. Ashlee and Fall Out Boy bassist Pete, 29, expect their first child this fall.

Photo by Kevin Mazur/WireImage.