Ben Stiller and Robin Williams spent a night filming inside the British Museum in London for the latest movie in their family comedy franchise.

Stiller reprises his role as security guard Larry in Night at the Museum: Secret of the Tomb, the third film of the series, and a large portion of it was shot at the British Museum, where he spent a memorable night with late actor Williams once the building was closed to the public.

He tells British newspaper The Independent, "It was really amazing and I felt like we really got to know it, being given private tours of different things... The Rosetta Stone was the thing I was most impressed with... It was Robin and me standing by the Rosetta Stone saying 'This is just the coolest thing ever'."

Stiller posted a picture on of the pair standing beside the tablet inscribed with three ancient languages.

Williams, who returns as former U.S. President Theodore Roosevelt for the third time, died in August (14), shortly after the movie was completed.

Stiller adds of his late friend, "I think the deeper the relationship with somebody, the more connection you have with that person, the harder it is to lose them. But then, the other side of it is, the more you keep of that friendship with you, so I am grateful for that."

Night at the Museum: Secret of the Tomb is released later this month (Dec14).