Omaha - Michael Phelps dropped one veil on Sunday, confirming his entry in the 400m individual medley at the US Olympic swimming trials.
Phelps, winner of the punishing event at the past two Olympics, had vowed after the 2008 Beijing Games that he wouldn't swim it again in major competition.
Even after his early entry in the event, he had indicated he might scratch. Instead, the deadline to pull out passed on Sunday with Phelps still slated for an intriguing match-up against Ryan Lochte in the first event of the eight-day meeting on Monday.
If he qualifies to race the 400m medley in London, Phelps gives himself an edge in a race with Japanese breaststroke star Kosuke Kitajima to become the first male swimmer to win the same Olympic event at three successive Games.
"I’ve always said I want to be the first to do something," Phelps noted on Saturday.
The men's 400m medley heats and final would come on the opening day of competition in London, while Kitajima's first chance could come in the 100m breaststroke final on day two.
Phelps could also have a chance to accomplish the feat in the 200m medley and the 100m and 200m butterfly - although he must book his berths in those events this week.
Two women swimmers have won three straight Olympic titles in the same event, Australian great Dawn Fraser in the 100m freestyle in 1956, 1960 and 1964 and Hungarian Krisztina Egerszegi in the 200m backstroke in 1988, 1992 and 1996.
Phelps holds the world record in the 400m medley at 4:03.84, set winning the gold in Beijing.
Lochte settled for bronze in Beijing behind Phelps and Hungarian Laszlo Cseh, but claimed the world title in Shanghai last year ahead of teammate Tyler Clary.
Phelps had been reconsidering his no-400 medley policy after some solid Grand Prix swims this season, and Lochte said he welcomed the chance to take on the Olympic superstar.
"I love racing against him," Lochte said. "He's one of the hardest racers in the world. He'll go toe-to-toe with you until the end. That's excitement for me. I really hope he does swim that."
Phelps is entered in seven events at the eight-day trials, where the top two finishers in each event book an Olympic place.
That raises the prospect he could vie for 10 medals in London, Phelps and coach Bob Bowman have been cagey about just which events he'll swim and what his goals are for his last Olympics.
Phelps said former US team-mate Erik Vendt had likened his London campaign -- in the wake of his unprecedented Beijing exploits - to putting the topping on an ice cream sundae.
"We've done a lot of cool, amazing things and now it's just time to have fun," Phelps said. "We're more relaxed and we'll see after this week what size cherry I want to put on top of my sundae."