Cinema-goers will see actor Robin Williams, who died earlier this year, reprise his role as one of America's most famous figures in his last screen appearance.
Williams, who shocked Hollywood and fans around the world when he took his own life in August, will be seen playing US President Theodore Roosevelt in the latest Night At The Museum movie, which he was working on at the time of his death.
Williams also played the famous President in the previous two films in the series.
The third instalment, Night At The Museum: Secret Of The Tomb, sees Williams and co-star Ben Stiller joined by former Downton Abbey actor Dan Stevens.
Stevens plays Knight of the Round Table Sir Lancelot, who helps the regular characters on their quest to save the magic of the Tablet of Ahkmenrah.
Speaking at a Press conference in London to launch the film, Stiller paid tribute to Williams, to whom the film is dedicated, saying: "Every time we got to work together on this movie franchise I was always excited, and he was very generous and kind, and would make everyone feel as if they were an equal."
Stevens said he was excited about appearing in the film, but after wearing a 50lb costume for four months, he joked: "I think I'm a couple of inches shorter than when I started."
The movie marks his return to comedy for the first time since he was a member of the Cambridge Footlights sketch troupe as a student. He is better known for his more serious period drama roles.