Watch: John Barrowman shared footage from the aftermath of the Berlin crash
The 55-year-old actor, singer and TV presenter is on holiday in the German capital with husband Scott Gill and posted a video on social media of himself taking shelter behind a tree as emergency crews arrived on the scene.
Barrowman told his 503k Twitter followers: "We think we have witnessed a terrorist attack here in Berlin... there’s a lot of people dead bodies all over the place...
"We’ve seen a car that came down the road and ended up in a storefront covering three city blocks it’s pretty horrific."
Berlin police say at least one person has died and around 30 were injured after the small car drove into the crowd outside the Kaiser Wilhelm Memorial Church in West Berlin before crashing into a shop front.
We think we have witnessed a terrorist attack here in Berlin we’re not sure there’s a lot of people dead bodies all over the place we’ve seen a car that came down the road and ended up in a storefront covering three city blocks it’s pretty horrific. #berlin pic.twitter.com/Xp1bkZBGt0
— John Barrowman MBE (@JohnBarrowman) June 8, 2022
It is not known if the driver intentionally struck the pedestrians but they have been detained.
Doctor Who star Barrowman said: "My friend told us to sit by a tree just in case anything else happens because it's between us and any other vehicles that might come."
He added: "It's really pretty bad. There's a dead body in the middle of the road and all the emergency services that are trying to help victims and people. There's a lot of people walking with limps and injuries. The car came down on to the pavement, then has come onto the road, hit somebody, gone down the road and come back onto the pavement and gone through a bunch of people and right into a storefront window.
"I heard the bang and the crash when we were in a store and we came out and just saw the carnage."
The former Dancing On Ice judge filmed helicopters circling over the scene before making his way back to his hotel.
He said he and Gill, his partner of 29 years, had phoned their parents to let them know there were safe and well.
The Scottish-born American actor is best known for playing Captain Jack Harkness in Doctor Who spin-off Torchwood.
He recently hosted ITV celebrity talent show All Star Musicals.
Last year Barrowman made a public apology after he was accused of sexual misconduct on the set of Torchwood.
The actor claimed he exposed himself as a prank claimed he did it to put people at ease, but apologised for any offence caused.