The 27-year-old from Baltimore stunned the world when he won eight titles at the last Olympics in Beijing four years' ago, more than any other athlete at a single Games, to bring his overall Olympic medal haul to 16 medals, 14 of which are gold.

Phelps (pictured above) will "only" be competing in seven events at London 2012 as he targets glory in the 200 and 400 metres individual medley, the 100 and 200m butterfly and three relay events over the next few days.

He needs just three medals of any colour at London 2012 to become the most successful Olympian ever ahead of gymnast Larisa Latynina who won 18 medals - nine gold, five silver and four bronze - for the former Soviet Union between 1956 and 1964.

Phelps is almost certain to achieve the milestone but admits that his final Olympics will be hard for him mentally.

"I'm more emotional because these will be the last competitive moments of my career," he said.

"Once I get into the pool I won't be holding back."

Ryan Lochte and Phelps prepare to swim in the championship final of the men's 200m backstroke at the 2012 US Olympic Swimming Team Trials

Standing in the way of Phelps and his place in the record books is American compatriot Ryan Lochte, who has become his biggest rival in recent years.

The pair will face-off in the 200m and 400m individual medley and a heated battle is expected after Phelps narrowly got the better of Lochte at the United States trials in June but the 14-time Olympic champion said he only wants to concentrate on himself.

"The only person I can control is myself," he said.

"If a record happens, great, but I don't think everything from my career has really sunk in and I think it will do after retirement."

Lochte has also looked to play down the rivalry.

"It isn't just going to be Michael and me swimming, the world's best will be in that pool aiming for gold," he said.

"It is great that there is so much attention on the two of us and I think we will be right up there but I'm not just looking at Michael; I'm looking at all the guys because they are all major threats."

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