The World: Chicago - Subway unveils tie-up with Olympic swimmer Phelps

Phelps has been in serious demand since winning a record-breaking eight gold medals at the summer Olympics in Beijing, and has already been aligned with brands such as Kellogg's Corn Flakes, Visa and Speedo.

Subway hopes to use its deal with Phelps to help promote its "healthy fresh" positioning. The brand spent more than $400 million on media last year, and has already outlaid more than $340 million in the first nine months of 2008.