Tour promoter Live Nation declined to comment; Billboard.biz will have more on this story as details emerge.
The tour was announced shortly before the singer's appearance on "Good Morning America" this morning.
Plans called for Iglesias, who is currently on tour in Europe, to be much more than a standard opening act; he was slated to carry full production on the Spears tour. While two such high-profile artists with top-shelf production values was sure to be attractive to fans, such an endeavor is also very expensive to produce.
Spears' tour will be produced by Live Nation, with veteran pop tour promoter Brad Wavra, VP at Live Nation, running point. Wavra has previously steered successful tours by such acts as Backstreet Boys, 'Nsync and the Jonas Brothers. Tickets will be available at Ticketmaster.com and LiveNation.com. Additional on-sale dates will be announced at a later date. Citi cardmembers will also have access to presale tickets through Citi's Private Pass Program.