Jordin Sparks, American Idol's youngest winner has been added as another opening act on Britney Spears' second leg of "The Circus Starring Britney Spears" tour. So if you're counting reasons to buy your tickets to the show: Jordin Sparks, Kristina DeBarge, $50 million production, 50 dancers, magicians, clowns, acrobats, and a 34 truck convoy to carry all the equipment from show to show. Britney is really outdoing herself on this tour, and it's showing in ticket sales. According to a press release, this is the highest grossing North American tour of 2009. Tickets are still available for the September 2 date at American Airlines Arena through Ticketmaster.