Standing atop the roof of Houston's NRG Stadium with drones illuminating an American flag in the night sky behind her, Lady Gaga kicked off her Super Bowl halftime set on Sunday by singing "God Bless America" as a subtle message of inclusion and unity in a deeply divided United States.

As many speculated about whether the outspoken singer would use her spotlight to address women's rights, immigration or President Donald Trump, Gaga recited part of the American Pledge of Allegiance, "one nation under God, indivisible with liberty and justice for all," in her opening song.

She then swung down from the roof to a stage suspended on cables and embarked on a meticulously choreographed 13-minute set of her greatest hits during the National Football League championship game between the New England Patriots and the Atlanta Falcons.

This year's Super Bowl followed a fierce presidential election campaign that Trump won in November but which left the country at least as fractured afterwards as before it began. Trump was greeted with massive protests just after taking office on Jan. 20, and his policy moves have sparked further protests and controversy in the first weeks of his presidency.

Ahead of her high-profile performance, watched by more than 100 million U.S. viewers, Gaga, 30, said in a post on the Instagram social media network that she planned to headline the slot entirely on her own, eschewing a tradition of halftime main acts bringing on special guests.

Dressed in a silver, sequined bodysuit and matching heeled boots, Gaga sang her dance hits "Poker Face" and "Born This Way" - an anthem for self-confidence and inclusion - as she performed aerial acrobatics while suspended in the air.

She then descended onto the stage to dance through "Telephone" and "Just Dance" before running through the crowd to a piano, where she sang her new song, "Million Reasons," giving a shout-out to her parents while she performed.

After joining her diverse cadre of dancers for "Bad Romance," the singer, known for her flair for the dramatic, ended her set by dropping her microphone, catching a football and jumping off a set of stairs onto the field.

While Gaga avoided making explicit political statements during her set, it was Renee Elise Goldsberry, Phillipa Soo, and Jasmine Cephas Jones, the Schuyler sisters on hit Broadway musical "Hamilton," who caused a stir with a subtle statement of support for women. 

As the trio sang "America the Beautiful" before the start of the game, they added the words "and sisterhood," in the first verse that contained the words "And crown thy good with brotherhood, from sea to shining sea."

The addition was immediately picked up on social media and became a top trend on Twitter.