Lady Gaga launched Joe Biden's inauguration ceremony in style by performing a dramatic rendition of the US national anthem.
Ahead of her performance of The Star-Spangled Banner, Gaga told her Twitter followers that she was praying for a day of peace.
She wrote: "My intention is to acknowledge our past, be healing for our present, and be passionate for a future where we work together lovingly.
"I will sing to the hearts of all people who live on this land. Respectfully and kindly, Lady Gaga."
Following Gaga's performance, chart-topper Jennifer Lopez belted out a triumphant medley of songs, including a rendition of Woody Guthrie's This Land is Your Land before transitioning to America the Beautiful.
"One nation under God, indivisible, with liberty and justice for all," Lopez then said in Spanish.
She also sang a few moments of her 2000 hit Let's Get Loud, before closing with more notes of America the Beautiful.
Country superstar Garth Brooks was also among the list of stars performing to celebrate the inauguration of the 46th President of the United States.
Brooks took off his black Stetson to sing an a cappella version of Amazing Grace and asked Americans at the ceremony, and watching at home, to singalong with him for the last verse.
Singer Katy Perry and an array of other artists including John Legend, Demi Lovato, Foo Fighters, Bruce Springsteen and Justin Timberlake are set to appear in a primetime inauguration special Celebrating America, hosted by Tom Hanks later in the evening.
Reese Witherspoon, Oprah Winfrey and Eva Longoria were among the celebrities who took to social media to celebrate the inauguration of President Biden and vice president Harris.
"This show of unity is so inspiring," Witherspoon wrote on Instagram.
Alongside a picture of Harris, the Oscar-winner added: "Such a powerful moment for the women of this country to be represented in the highest office."
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Broadcaster Winfrey said she was "in tears watching this extraordinary moment for women in the US and the world" alongside an image of Harris taking the oath.
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Desperate Housewives star Longoria also welcomed the swearing-in of the new president and vice president.
She tweeted: "Today, we make history! Today, we celebrate leaders like President Joe Biden and our first Madam Vice President, Kamala Harris.
"Today is only the beginning."
Actress Kerry Washington said there is "much work to do" following the inauguration of President Biden.
She added on Twitter: "But TODAY I want to celebrate. And pray. And revel in our tremendous power (even against all odds) to make history happen."
Talk show host Jimmy Fallon also congratulated the new president and vice president.
"I'm honored and proud to witness this moment in history," he tweeted.
Author Stephen King tweeted: "This is a pretty beautiful event."
The heavy Hollywood presence for President Biden's inauguration stands in stark contrast to the entertainment industry's stance towards his predecessor.
