Gascoigne has played with John Williams in film scores on the original Star Wars trilogy, Superman, and Harry Potter and the Goblet of Fire. He has also played marimba with guitarist John Williams (no relation) in his ensemble John Williams & Friends and has recorded with Shirley Bassey and Cleo Laine. Gascoigne scored a few films of his own, including 1972's Under Milk Wood (with Peter O'Toole and Elizabeth Taylor). He played synthesizer for Jerry Goldsmith on Rambo, Outland, and Supergirl, played piano on Gosford Park, and arranged the 2000 film version of Love's Labour's Lost.