She is only the second person, and the youngest, to win all four top Grammys on the same night.

Eilish, distinguished by her green hair and baggy clothes, recorded the album with her brother Finneas in the bedroom of their Los Angeles home. Finneas also won the Grammy for non classical producer of the year.

They seemed taken aback by their Grammy haul, which saw them triumph over established stars including Taylor Swift, Ariana Grande and rapper Post Malone.

"We didn't make this album to win a Grammy. We wrote about depression and suicidal thoughts and environmental change," Finneas said as the pair accepted the awards. "We stand up here confused and grateful."

Asked backstage what she would do next, Eilish said, "Being in this moment is all I'm thinking about... I'm gonna do whatever I feel."

The Grammy Awards show opened with a dedication to basketball star Kobe Bryant, who died in a helicopter accident earlier in the day and whose Los Angeles Lakers team has its home at the city's Staples Center and Grammy venue.

"We are literally standing here heartbroken in the house that Kobe Bryant built," said Grammy host Alicia Keys. "We never imagined in a million years we'd have to start the show like this."

R&B star Lizzo won three of her eight nominations, while gay black country rapper Lil Nas X took two for his viral "Old Town Road" collaboration with Billy Ray Cyrus.

Lil Nas X, 20, wearing a cowboy hat and silver lure suit, and country singer Billy Ray Cyrus dazzled the house with a kitschy performance of their viral collaboration "Old Town Road," with contributions from stars ranging from K-Pop band BTS to young yodeler Mason Ramsey.

"He told the world he was gay and overnight he became an inspiration and a role model for hundreds of young people around the world," comedian Ellen DeGeneres, who is also gay, said as she introduced Lil Nas X.

Grande performed a medley of hits from her break-up album "Thank u, Next," including "7 Rings" and "Imagine" but won none of the five Grammys for which she was nominated.

Slain rapper Nipsey Hussle, 33, who was gunned down in his Los Angeles neighborhood last year, won two Grammys and was honored in a tribute by John Legend, DJ Khaled and rapper Meek Mill.

Blake Shelton and his fiancee Gwen Stefani held hands as they debuted their new romantic duet "Nobody But You," while Camila Cabello sang her recent single "First Man" to her tearful father in the audience. Demi Lovato won a standing ovation in her first performance at a major awards show since a drugs overdose in 2018.

The Grammy winners are chosen by members of the Recording Academy, which is currently embroiled in a dispute over the departure of its new chief executive Deborah Dugan and her allegations of conflicts of interest in the nominations process. The Recording Academy has denied the allegations.