Michelle Obama took to Twitter on Saturday night to congratulate Michael Phelps.
"Wow @MichaelPhelps! Barack & I have been cheering you on! We're so proud of you & what you've accomplished," the First Lady wrote.
The U.S. swimming champ took gold in his final Olympic race on Saturday. The win is the 18th gold and 22nd overall medal of his Olympic career.
Obama also congratulated Phelps on Tuesday night after his record-breaking victory.
Check out the tweet below.
Rulon Gardner - 2000 Sydney
American Rulon Gardner pulled off a stunning upset, defeating Russian wrestling icon Alexander Karelin to win the Olympic super heavyweight wrestling gold medal. <a href="http://sportsillustrated.cnn.com/olympics/2000/wrestling/news/2000/09/27/gardner_upset_ap/" target="_hplink">He ended Karelin's 13-year unbeaten streak. </a>
Men's Basketball -- 1972 Munich
The gold medal basketball game between the U.S and the Soviet Union was marred by a controversial finish, with the <a href="http://espn.go.com/classic/s/Classic_1972_usa_ussr_gold_medal_hoop.html" target="_hplink">Soviets</a> scoring an unexpected upset thanks to some help from the scorer's table. The U.S. still hasn't accepted the silver medals.
Abebe Bikila - 1960 Rome
The Ethiopian marathoner became the <a href="http://www.bbc.co.uk/news/world-africa-18862683" target="_hplink">first black African</a> to win an Olympic gold medal when <a href="http://www.time.com/time/magazine/article/0,9171,1829863,00.html" target="_hplink">he famously ran barefoot</a> to victory.
Jesse Owens - 1936 Berlin
Jesse Owens <a href="http://espn.go.com/sportscentury/features/00016393.html" target="_hplink">won four gold medals</a> in Germany, providing a very public counterpoint to Adolf Hitler's views on Aryan superiority.
Greg Louganis - 1988 Seoul
American diver Greg Louganis suffered a concussion after accidentally hitting his head on the springboard during the diving preliminaries. Despite the frightening nature of the incident, <a href="http://sportsillustrated.cnn.com/multimedia/photo_gallery/0807/top.20.olympic.summer.moments/content.11.html" target="_hplink">he still went on to win two gold medals. </a>
Jim Thorpe - 1912 Stockholm
Jim Thorpe<a href="http://www.olympics30.com/30greatest/jim-thorpe-hero.asp" target="_hplink"> won both the pentathlon and decathlon</a> in Stockholm. His medals were stripped the next year when it was revealed that he had played some semi-professional baseball before the Olympics. The medals were reinstated in 1982.
Babe Didrikson - 1932 Los Angeles
A pioneering female athlete, Babe Didrikson was a multi-sport star throughout her life. In 1932, she won the <a href="http://espn.go.com/sportscentury/features/00014147.html" target="_hplink">first women's Olympic javelin gold medal</a> while also capturing gold in the 80-meter hurdles.
Alice Coachman - 1948 London
In 1948, track star Alice Coachman became the <a href="http://www.teamusa.org/News/2012/January/01/London-Re-Calling-Home/London-ReCalling-Series-Alice-Coachman.aspx" target="_hplink">first African-American woman to win an Olympic gold medal </a>with a victory in the high jump.
Bob Beamon - 1968 Mexico City
Bob Beamon's amazing (and totally unexpected) leap broke the <a href="http://www.guardian.co.uk/sport/blog/2011/nov/23/50-stunning-olympic-bob-beamon" target="_hplink">long-jump world recor</a>d in the 1968. Beamon's flight was so unprecedented that judges had to get <a href="http://sportsillustrated.cnn.com/vault/article/magazine/MAG1081936/index.htm" target="_hplink">an old-fashioned measuring tape</a> to record it.
John Carlos and Tommie Smith - 1968 Mexico City
Track and field stars John Carlos and Tommie Smith made a fierce political statement and created an enduring image with their <a href="http://www.guardian.co.uk/sport/blog/2012/feb/08/olympic-moments-tommie-smith-john-carlos" target="_hplink">defiant raised, gloved fists</a> after winning the gold and bronze medals, respectively, in the 200-meters in Mexico City.
Munich Massacre - 1972 Munich
In the darkest chapter in Olympic history, 11 Israeli athletes and coaches were <a href="http://sports.yahoo.com/news/olympics--munich-massacre.html" target="_hplink">taken hostage and killed</a> by Palestinian terrorist group Black September during the 1972 Games.
Mary Decker - 1984 Los Angeles Olympics
Mary Decker was the heavy favorite to win gold in the women's 3,000-meter event, but got <a href="http://sports.espn.go.com/espn/espn25/story?page=moments/72" target="_hplink">tangled up with Zola Budd and fell to the ground. </a> Her agony on the track as the racers went on without her captured the passion of these athletes. <em>Correction: This slide previously misidentified the year of Decker's fall as 1976.</em>
Derek Redmond - 1992 Barcelona
Derek Redmond suffered a hamstring injury during the 400-meter semifinal but insisted on finishing the race. As he limped toward the finish line, <a href="http://sports.espn.go.com/espn/espn25/story?page=moments/94" target="_hplink">his father emerged from the stands to</a> help him make it.
Nastia Liukin - 2008 Beijing
Nastia Liukin won the gold medal in the women's <a href="http://www.msnbc.msn.com/id/26211786/ns/beijing_olympics-beijing_olympics_news/t/nastia-liukin-wins-gold-all-around/#.UAX4QHBaK3k" target="_hplink">gymnastics all-around</a>, barely beating U.S. teammate Shawn Johnson.
Mary Lou Retton - 1984 Los Angeles
Mary Lou Retton became the <a href="http://www.marylouretton.com/new_site_biography.htm" target="_hplink">first American woman to win a gold medal </a>in gymnastics at the 1984 Games. All told, the petite dynamo <a href="http://www.ighof.com/honorees/1997_Mary_Lou_Retton.php" target="_hplink">won five medals</a> and a nation of new fans.
Muhammed Ali - 1996 Atlanta
The 1960 Olympic gold medalist and heavyweight boxing champion emerged as the <a href="http://www.nbcolympics.com/video/2012/1996-muhammad-ali-lights-the-flame.html" target="_hplink">surprise torchbearer to light the cauldron</a> and open the Atlanta Games. Known to be <a href="http://www.bbc.co.uk/sport/0/olympics/18088134" target="_hplink">suffering from Parkinson's disease</a>, Ali's presence became one of the most memorable aspects of those Games.
Kerri Strug - 1996 Atlanta
By sticking the landing in the vault <a href="http://sports.yahoo.com/news/olympics--kerri-strugg--u-s--gymnastics--conquering-hero-of-the-olympic-ideal.html" target="_hplink">on an injured ankle, </a> Strug helped the US. gymnastics team win Olympic team gold.
Michael Johnson - 1996 Atlanta
Sporting a pair of gold shoes, Michael Johnson put on quite a show <a href="http://sports.yahoo.com/news/olympics--michael-johnson-s-golden-runs-in-1996-live-on-in-olympic-history.html" target="_hplink">in Atlanta</a>, winning two gold medals and setting a world record in the 200 that last for more than a decade.
Usain Bolt - 2008 Beijing Olympics
The Jamaican track star <a href="http://www.usain-bolt.eu/usain-bolt-records/" target="_hplink">set world records </a>in the 100m, 200m and 4x100m relay in a thoroughly dominant showing.
The Dream Team - 1992 Barcelona
Opponents of Team USA were more focused on getting photographs with the American players than beating them. Of course, this is probably for the best as there may not be a team that has ever played that could have matched up against a <a href="http://www.nba.com/history/dreamT_moments.html" target="_hplink">team able to mix and match Hall of Famers</a> like Michael Jordan, Magic Johnson, Charles Barkley, Karl Malone, Patrick Ewing, Larry Bird. The list goes on longer than the competitive portions of most games lasted.