March Madness 2013 kicked off on Sunday when the full bracket list for the NCAA men's basketball tournament was revealed by CBS.

Sixty-eight teams will be in the hunt for college's basketball championship title and many celebrities took to social media to express their excitement and to cheer on their favorite teams.

Singer John Legend, who is an alum of Ohio State University, tweeted, "Congratulations to THE Ohio State University! Big 10 champs!" By winning the Big 10 conference title, Ohio State secured a two-seed. The Buckeyes will face No. 15-seed Iona College.

The first four games of the NCAA Tournament will be played on Tuesday and Wednesday. The second round games take place on Thursday and Friday. The third round will be contested over the weekend on the March 23 and 24, while the Sweet 16 and Elite Eight games will go run through the 28-31.

Jimmy Kimmel congratulated his alma mater UNLV, tweeting, "Go forth, Rebels! @UNLVRebellion."

Rapper Nelly supported his hometown college team, the Saint Louis University Billikens. He tweeted, "Congrads to SLU #4 seed in tournament !!! GO GETTEM Stlouis !!! !!!!!"

Actress Ashley Judd was disappointed when her alma mater University of Kentucky was not selected to play in the tournament.

"Offsetting March Sadness w/ KY schools WKY & UoL dancing (& w/ such style)," she tweeted. The Wildcats won the Men's NCAA championship in 2012 and will travel to Robert Morris on Tuesday for a shot at winning a National Invitation Tournament championship.

Director/Die-hard Knicks Fan Spike Lee got into the March Madness spirit by sending out multiple tweets about his hometown college.

"Good Luck To LIU/BROOKLYN BLACKBIRDS In Play In Game Against James Madison-MARCH MADNESS," he tweeted. The Blackbirds were able to nab a No.16 seed and will play James Madison in the first round of the tournament.

Lee also congratulated VCU's coach Shaka Smart by saying, "Good Luck To Coach Shaka "Havoc" Smart And The VCU Rams For The Upcoming NCAA Tournament."

Rapper T.I. showed support for the University of Memphis, posting, "Congrats @UofMTigersHoops CUSA 2013 Conference Champs!"

The championship game of the men's tournament will take place at the Georgia Dome in Atlanta, Ga. The Regional championships will be held at the Staples Center in Los Angeles, Calif., the Verizon Center in Washington D.C., Cowboys Stadium in Dallas, Texas, and Lucas Oil Stadium in Indianapolis, Ind.