On Saturday night, during Gaga's concert at the Park Theater in Las Vegas, USA, Cooper appeared on stage to make her a surprise.
The film "A Star is Born", which brought together Bradley Cooper and Lady Gaga on the big screen, started a friendship between the actor and the singer.
"Hello Vegas" said the singer, as he calmly entered on stage before starting to sing "Shallow". Lady Gaga, surprised and visibly moved, eventually went to the piano and joined her colleague for a duet.
The moment was captured by the fans and published on social media.
Read more in Jornal de Notícias