WATCH: Lady Gaga in tears as she takes Oscar for best original song

Hollywood, United States: Lady Gaga is a Grammy winner many times over. On Sunday, the pop diva became an Oscar winner, taking the trophy for best original song for her power ballad "Shallow" from "A Star Is Born."

Before accepting the award at the Dolby Theatre, Gaga belted out the number with her co-star Bradley Cooper.

On stage, she was tearful.

"There´s not a single person on the planet that could have sang this song with me but you. Thank you for believing in us," she said to Cooper, who also directed the film, the latest reimagining of the classic Hollywood tale.

The singer, also a nominee for best actress, then offered a message to aspiring artists like her character in the film, Ally, who gets her big break when she meets troubled rocker Jackson, played by Cooper.

"This is hard work. I've worked hard for a long time, and it´s not about, you know, it´s not about winning. But what it´s about is not giving up. If you have a dream, fight for it," Gaga told the audience.

"There´s a discipline for passion, and it´s not about how many times you get rejected or you fall down, or you´re beaten up. It´s about how many times you stand up, and are brave, and you keep going."

"Shallow" bested songs from superhero blockbuster "Black Panther," documentary "RBG," Coen brothers film "The Ballad of Buster Scruggs" and Disney reboot "Mary Poppins Returns."