Perhaps the all-time greatest performer at the Games is participating in his last individual event at the Olympics.
Michael Phelps is set to swim in the men's 100m butterfly at 2:38 p.m. ET in London. The race won't be broadcast on NBC until primetime, but you can watch a live stream online by clicking here.
Phelps is looking to improve on his medal records. On Thursday, he won his 16th gold and 20th total medal of his career by finishing first in the men's 200m individual medley. He narrowly beat out his U.S. teammate, Ryan Lochte, who took the silver.
Unlike in his competition against Lochte, Phelps is a heavy favorite to take home the gold on Friday. His odds of coming in first have been set at 1/7 by Bovada, the online betting Web site. The American had the best time in the semifinals at 50.86 seconds.
South Africa's Chad le Clos probably has the best chance of pulling the upset. His odds are set at 16/1. Serbia's Milorad Cavic and Tyler McGil from the USA are also in the running to medal in the race.
The world record for the 100m butterfly is held by Phelps. He recorded a time of 49.82 seconds in Rome in 2009.
A win for Phelps would be the third straight gold medal for Phelps in the event. He is the only Olympian in history to win the same individual competition at three straight Games.
He is also scheduled to race in the 4x100m medley relay on Saturday.
Here is the complete startlist for the 100m butterfly at the 2012 Olympics:
1 Konrad Czerniak (POL)
2 Joeri Verlinden (NED)
3 Tyler McGill (USA)
4 Michael Phelps (USA)
5 Chad Le Clos (RSA)
6 Milorad Cavic (SER)
7 Steffen Deibler (GER)
8 Yevgeny Korotyskin (RUS)