Theophilus Musa London is an American rapper, singer, and record producer. He is best known for his guest appearance alongside Allan Kingdom and Paul McCartney on Kanye West's 2015 single "All Day", which received two Grammy Award nominations. London has also worked on West's demo album Donda 2 (2022), as well as many of his other unreleased projects.

"All Day" is a song by American rapper Kanye West. It features Trinidadian-American rapper Theophilus London, Canadian rapper Allan Kingdom, and English musician Paul McCartney. The song was produced by West and ten others, including Puff Daddy, French Montana and Travis Scott. Having initially leaked in August 2014 after being announced for release as a single by West, he premiered the song on March 2, 2015 via Power 106 and Hot 97. The following day, it was released for digital download and streaming as a standalone single, through GOOD Music and Def Jam. The song contains a re-recorded sample of "When the Wind is Blowing" by Paul McCartney and Wings and an interpolation from "Dance with Me" by Jamaican singer Noel Ellis. It includes elements of industrial and drill music, alongside synthesizers. The lyrics center around West's success in life and the music industry; he compares himself to "both MJ's".