Ellen DeGeneres Stars in Mock 'A Star Is Born' Trailer

The talk-show host took over Lady Gaga's role of Ally in the fake trailer.

While Lady Gaga is already earning praise for her role as unknown singer-songwriter Ally in the upcoming film A Star Is Born, Ellen DeGeneres jokingly revealed to her audience on Thursday that she was originally cast in the role.

The Ellen DeGeneres Show host then shared a version of the trailer that features her in the starring role. The mock trailer opens with Bradley Cooper's character, Jackson Maine, telling DeGeneres that he thinks she is beautiful. The talk-show host wears a cowboy hat and an all-denim ensemble.

"Hey, I just wanted to take another look at you," Maine says in another scene before DeGeneres is seen standing in front of a trailer holding a washboard instrument against her chest.

Another clip shows DeGeneres dancing onstage clad in another all-denim look and donning long pigtails and a cowboy hat.

DeGeneres is later seen emotionally lip-syncing to Gaga's rendition of "Shallow" in front of an excited audience. A montage of clips then shows her singing to different crowds, though she wears the same outfit and continues to carry the washboard with her. She eventually plays the instrument near the end of the trailer.

The mock trailer concludes with her dancing alone in front of a black backdrop as the name of the film appears onscreen.

Watch the mock trailer for A Star is Born above.