Ben Stiller, Owen Wilson Robin Williams and the rest of the Night of the Museum gang made the trip across the Atlantic to London for the final instalment of the franchise, and even hooked up with Aussie Rebel Wilson and south London’s own Dan Stevens.

Secret of the Tomb is the third of the series - which stars Stiller a night watchman Larry Daley in a museum where the exhibits come to life - sees the source of their magic (an Egyptian tablet) losing its power.

To find a solution, Larry and his cohorts – including Robin Williams’ Teddy Roosevelt, Owen Wilson’s cowboy Jedediah, Steve Coogan’s Roman Octavius and the capuchin monkey Dexter – travel to London where the tablet’s creator, Merenkahre (Sir Ben Kingsley) can hopefully reveal its secrets and restore its power.

It’s knockabout family fun with a nice angle on fatherhood and growing up, which brings the franchise to a neat conclusion.

At a press conference at Claridge’s, director and producer Shawn Levy said: “The city of London played a crucial role because we realised after the second movie that we had never really gone beyond the museum walls.

“There was central idea of spilling out from the museum and these characters colliding with the real world – Trafalgar Square, the West End and various places.”

He added: “The British Museum was amazing. We actually filmed more inside the British Museum than we have ever filmed in any museum in the whole franchise.”

Making his debut in the series is 32-year-old former Downton Abbey star Dan Stevens as Lancelot.

The actor, who was born in south London, relished the chance to play a funny role.

He said: “It was really nice to do some comedy. I haven’t done any since I was at college.

“I’ve followed quite a straight-laced path since then, costume drama and that sort of thing, so yeah it was delightful to get to work alongside these guys who are world class improvisers and to learn that art as we went along was amazing.”

It wasn’t all rosy for Dan, whose role involved romping around in a 50 pound suit of armour.

He said: “I hadn’t quite appreciated that when taking the role on.

“When we were rehearsing the sword fights, without the armour most of the time, I got the hang of that.

“Trying everything with the armour on, it wore me down.

“I had a very bad back by the end.”

Aussie Rebel Wilson also makes her first appearance as British museum guard Tilly and said she used her famous flatmate to nail the English ways.

Rebel said: “I live with a great British comedian, Matt Lucas, so I tried to channel him a little bit – a bit cheeky.

“I love being a bit street as well, because that’s just how I like to roll. Like a gangster.”

The film sees Ben Stiller’s character’s role as keeper of the living museum creatures pass to Wilson’s, though director Levy is coy on whether the franchise could be reborn as with her in the lead.

He said: “I think right now in our minds, this third movie brings closure to the franchise and to the characters.

“I suppose that we can’t predict the future and definitely we have come to love Tilly the nightguard. We shall see.”

Sadly, one character who definitely won’t be returning is Teddy Roosevelt, who was played by Robin Williams who died this year.

Ben Stiller said: “I never took for granted being able to work with Robin.

“I was always a huge fan of his and, growing up, for me he was always one of my comedic idols and this was the only chance I had to work with him.

“Every time we got to work together in these movies was exciting.

“He was very generous and kind and would make everybody feel as if they were an equal.

“It was fun to be around him and have him treat you that way but really under the surface I was just a fan so I feel really lucky to have had that opportunity to spend time with him and be in movies with him.”

Night at the Museum: Secret of the Tomb (PG) is out Friday (December 19)