A low-flying helicopter filmed him running along it. Traffic was halted on nearby Blackfriars road bridge and boats kept from the area while the shoot for Mission: Impossible 6 took place.
Cruise is famed for performing his own stunts. Last year he was injured when jumping between two buildings on a shoot in the capital.
He was seen jumping from roof top to roof top but missed his landing spot, instead slamming into the side of the building before getting up and hobbling around.
An insider at the time said: “The injury is worse than was at first feared. Tom did serious damage and will need months to recover.
On Saturday, he seemed back in fine form as he warmed up in a thick jacket on the bridge roof.
Below, Thameslink trains continued passing through the station as normal – full of passengers unaware that one of the world’s most celebrated action stars was just yards above.
Over the course of several takes Cruise stripped off his coat and darted south across the river, before quickly wrapping up again.