Kelly Clarkson

Kelly Clarkson

Beyonce, Kelly Clarkson and James Taylor saluted U.S. President Barack Obama in Washington, D.C. on Monday by performing at his inauguration ceremony.

"And THAT'S why she's the No1 performer in world music.....incredible! Beyonce inauguration"

Obama was sworn in for a second term with Vice President Joe Biden in front of more than 800,000 people on the National Mall and Taylor was among the first to help celebrate the momentous occasion with an acoustic version of America the Beautiful.

Clarkson stepped up to sing the stirring My Country 'Tis of Thee, taking the microphone after a powerful speech from President Obama, who vowed to stand up for equal rights and address issues of climate change, immigration and same sex marriage during his next four years in office.

Beyonce then brought the event to a close by belting out a flawless rendition of the National Anthem, The Star-Spangled Banner, backed by the U.S. Marine Band.

Actress Eva Longoria, who is a co-chair of Obama's inauguration committee, Katy Perry, John Mayer and Beyonce's rap superstar husband Jay-Z were among the stars in attendance at Capitol Hill, while a host of other celebrities tuned in to watch the televised celebration from home and took to Twitter.com to share their comments with fans.

Designer Nicky Hilton writes, "It's official! Congrats Mr President!" and director Kevin Smith tweets his approval, posting "I like this President and his First Family. Glad he got his second term he seems like a good guy".

Applauding the performers, New Kids on the Block star Joey McIntyre comments, "KellyClarkson gave me chills. She rocked it!! (Always does). Great speech by POTUS (President of the United States)!!!", while Bette Midler praises Beyonce, stating "The hardest song in any repertoire, the National Anthem.... She sang beautifully"

Actress Olivia Wilde also took to the web to, as she exclaimed, "Yea B!!!!!!! Lookin smokin. Hot damn. She wins 'hottest in the cold'".

CNN newscaster Piers Morgan writes, "And THAT'S why she's the No1 performer in world music.....incredible! Beyonce inauguration", and the R&B diva's sister Solange Knowles simply tweets, "I couldn't be more proud on this day".