J.Lo at 40: How a Diva Was Made!

In 40 photos, see how the birthday girl (on July 24) went from Jenny from the Block to superstar


While on the El Cantante tour with hubby Marc Anthony, a wind machine offers a glimpse underneath Lopez's flowing Roberto Cavalli-designed costume – revealing a prominent baby bump at the Oct. 3, 2007 stop in Uncasville, Conn. "I used a lot of stretch fabrics," Cavalli tellingly tells PEOPLE of his tour outfits.