Michael Phelps
The most decorated Olympic athlete ever—16 medals, including 8 gold in Beijing—heads to London more than ready to defend all his bling.
Lolo Jones
After finishing third at the Olypmpic trials, the virginal athlete secured a spot on Team USA. She'll be competing in the 100-meter hurdles. Her first Olympic appearance was in Bejing—after clipping a hurdle, she lost the race she was favored to win.
Ashton Eaton
At the U.S. Olympic trials, the decathlete set a new world record after earning 9,039 points. The first-time Olympian heads to London as favorite to win the gold.
Zara Phillips
Queen Elizabeth II's eldest granddaughter will be saddling up to compete on Great Britain's eventing team. London marks the first Olympics for the equestrian and her aptly named steed, High Kingdom.
Rafael Nadal
He may have recently left Wimbledon after a surprising defeat, but the Spaniard will be heading back to the All England Lawn Tennis and Croquet Club to defend his 2008 gold medal in men's singles.
Allyson Felix
After a tie in the 100-meter trials left the three-time medalist's hopes for London uncertain, the American sprinter secured her spot after finishing first the 200-meter trial at 12.69—a personal best.
Yelena Isinbayeva
The Russian pole vaulter won gold at both Athens and Beijing and will defend her title in London.
Roger Federer
The decorated star has won just about every tennis title around—except singles gold. Shortly after finishing up Wimbledon, the Swiss star—who took home doubles gold in Beijing with partner Stanislas Wawrinka—will return to the famous court in hopes of snagging the top prize.
Paula Radcliffe
After disappointments in Athens and Beijing, the marathoner—who holds the is the current world record for women—is a favorite to win the gold on her home turf.
Matthew Mitcham
Perfect 10! The Australian diver is surely hoping for a repeat of his 10-meter gold—and impressive score—earned at the 2008 games.
Camille Adams
After snagging the top spot in the 200-meter butterfly at the Team USA trials, the swimmer heads to London, her first games.
Wu Peng
The Chinese athlete is one of just a few to give Michael Phelps a run, er, swim, for the top prize. In 2011, the two-time Olympian bested Phelps in the 200-meter butterfly, an event the American had not lost in nearly a decade.
Hope Solo
Team USA hopes to defend the gold medal they took home from the 2004 games and with Solo as goalkeeper, they're in good hands.
Mark Cavendish
Just days after finishing up the Tour de France, the Manxman plans to pedal home to the U.K. with hopes of adding an Olympic medal to his many championship jerseys.
Venus Williams & Serena Williams
After the excitement of Wimbledon, the sisters will defend their 2008 doubles gold. The tennis phenoms will also compete in singles.
Bob Bryan & Michael Bryan
Hoping to add a gold medal to their dozens of other wins, the twins (and bronze medalists in Beijing) head into their third Olympics with all four eyes on the top prize.
Kerri Walsh & Misty May Treanor
Talk about double trouble! The American duo snagged beach volleyball gold in Athens and Beijing. Here's hoping for a three-peat in London.
Ryan Lochte
Jeah! London marks the third Olympics for the swimmer. The six-time medalist heads to the games competing in multiple events including the 200-meter backstroke, the 200-meter IM and the 100-meter butterfly.
Aliya Mustafina
The 17-year-old gymnast hails from Russia and competes in vault, uneven bars, balance beam and floor exercise. She is focusing on rehabilitating a knee injury as she prepares for her first Olympics.
Kosuke Kitajima
No stranger to the Olympics (having competed in both Athens and Beijing), the world record setting Japanese swimmer locked down gold medals both years for the 100 and 200-meter breaststroke.
Jessica Ennis
Though she missed out on the Beijing Olympics due to stress fractures, the English track and field star will compete in hurdles this year. Oh yeah, and she's also a heptathlon and pentathlon world champion.
Kohei Uchimura
The Japanese gymnast previously competed in the Beijing Olympics, where he competed in floor exercises, vault, parallel bars and the high bar. He took home two silver metals for team and all-around.