WATCH: Bradley Cooper joins Lady Gaga on stage in Las Vegas for 'Shallow'

LAS VEGAS (KTNV) — If you were at the Lady Gaga show on Saturday night in Las Vegas, you were in for a real treat.

Lady Gaga pulled her “A Star Is Born” co-star Bradley Cooper on stage to perform the Oscar-nominated song “Shallow” live for the first time ever since the movie hit the big screen.

The actor turned singer and singer turned actor hugged before Lady Gage gave Cooper a pair of "in-ears" and a microphone.

Cooper then said “Hello Vegas” before he started singing. After the performance, he reportedly threw a hat into the crowd.

Lady Gaga and Cooper are nominated for Best Actress and Best Actor Oscars from the Academy of Motion Picture Arts and Sciences. The movie was also nominated for Best Movie. The pair are scheduled to sing the duet during the 91st Academy Awards show on Feb. 24.

Gaga's show "Enigma" opened at Park Theater at Park MGM in Las Vegas in late December. The song is the highlight of the show for many attendees and the crowd sings along whenever it is performed. It has also been nominated for four GRAMMY awards.