Michael Phelps is eagerly anticipating a showdown with Ian Thorpe at next year's London Olympics, should the Australian choose to race the men's 200 metres freestyle and set up another 'Race of the Century'.

Thorpe has returned to the pool after quitting competition in 2006 and is targeting next year's London Olympics - where he is expected to concentrate on three events, the 200 freestyle and the 4x100 and 4x200 freestyle relays.

Phelps and Thorpe, along with Pieter van den Hoogenband provided a memorable showdown in the 200 freestyle at the Athens Olympics in 2004, which was dubbed the 'Race of the Century' and Phelps insists another showdown in London could be just as exciting.

"The 200 free has turned into a fun event," Phelps told a small gathering of reporters in Shanghai, a day after the world swimming championships ended.

"Just being able to have the chance to swim in a race with Thorpe again is something I will be looking forward to.

"I've only had two races with him in my career and being able to have him back in the pool will be exciting for the sport."

Phelps, the most successful Olympian ever who won an unrpecedented eight gold medals in Beijing, finished seond behind compatriot Ryan Lochte in the 200 freestyle at Shanghai but it was the closeness of the finish that had him excited.