Police have launched a manhunt for the attacker after the shooting in the Hampstead Heath area of the city.
The shooting happened at around 9.24pm on Sunday night at the junction of Mansfield Road and Roderick Road in the London Borough of Camden.
A man is being treated by paramedics after being shot in the leg.
No arrests have been made and no guns have been recovered from the scene.
A Met Police spokeswoman told Daily Star Online: "Police were called by colleagues...
source: Daily Star