Bradley Cooper makes surprise appearance on Glastonbury Festival stage

Actor Bradley Cooper surprised fans by taking the stage at the GlastonburyFestival Friday, since he wasn't exactly part of the lineup.

The Hangoverstar was shooting a scene for the upcoming filmA Star Is Born, which he is also directing. Lady Gaga, Sam Elliott and Dave Chapelleare also part of the cast.

• Lady Gaga, Bradley Cooper to headline A Star Is Born remake

The film is a remake ofa story about awoman who begins her ascent in show business and becomes involved with another musician who soon finds his career on the decline. The 1954musical featuredJudy Garland and the 1976 drama starred BarbraStreisand and Kris Kristofferson.

In fact,Kristofferson, who co-starred with Cooper in the 2009 romcomHe's Just Not That Into You,was next to performon stage after the shoot wrapped. Cooper introduced him and thanked thecrowd.

The American Sniper actor also filmed scenes at the Coachellamusic festival in Indio, Calif. in April alongside Lady Gaga. In that instance, festival-goers were told about it in advance.

Cooper was caught on camera again at Glastonbury when hephoto-bombeda pictureby musicianChris Simmons, who was snapping a selfie withBrad Pitt. The Moneyball actor was also attending the music fest.

A Star Is Born is expected to hit theatres in September of 2018.