Two murals by street artist Banksy have sprung up in central London.
The works, marking the opening of an exhibition by American artist Jean-Michel Basquiat, appeared in a tunnel near the Barbican Centre. Banksy described the murals as an "(unofficial) collaboration" in a series of Instagram posts.
Basquiat first rose to fame as a New York City graffiti artist, before turning his hand to painting. He died in 1988, aged just 27, from a suspected drug overdose.
Basquiat: Boom for Real opens at the Barbican Centre on Wednesday.