‘Night at the Museum: Secret of the Tomb’ Trailer: Ben Stiller Meets Sir Lancelot From ‘Downton Abbey’ (Video)

Dan Stevens plays the knight famous for hooking up with King Arthur’s wife

Ben Stiller is traveling to London in “Night at the Museum: Secret of the Tomb” and hanging out with former “Downton Abbey” star Dan Stevens as famed knight Sir Lancelot.

The first trailer (above) for the upcoming comedy shows some of the antics audiences have to look forward to, while filling them in on the plot: The magic tablet that brings history alive at night is losing its power, so Stiller’s character must team up with a few favorite mannequins to figure out why.

See video: First Trailer for ‘The Hobbit: The Battle of the Five Armies’ Hits the Web

Ben Kingsley joins the 20th Century Fox franchise as an Egyptian Pharaoh and Rebel Wilson plays a British security guard, while Robin Williams, Owen Wilson and Ricky Gervais return.

See video: Watch The Roots Watch the ’50 Shades’ Trailer on Fallon

The third “Night at the Museum” movie hits theaters on Dec. 19.