WATCH: Lady Gaga joins U2 on Las Vegas' Sphere stage to sing iconic song

U2 had a special guest join them during last night's Las Vegas show at the Sphere.

Pop superstar Lady Gaga joined Bono in signing 'Shallow' from the movie 'A Star Is Born'.

U2 are performing gigs at the iconic Sphere venue until February 2024.

Watch a clip of Bono and Gaga dueting below (Footage from Lady Gaga Now):