The first trailer has arrived for director Joe Cornish's The Kid Who Would Be King, revealing a lighthearted, modernized take on Arthurian legend -- and a blink-and-you'll-miss-it appearance by Patrick Stewart as Merlin.

The film follows a put-upon British schoolboy named Alex who finds the legendary sword Excalibur in the ruins of a building, and draws it from the rubble. Soon thereafter, Alex is confronted by the wizard Merlin in the guise of a classmate who helps him to accept his destiny as Britain's defender when the evil sorceress Morgana (Rebecca Ferguson) threatens to return with an army of the undead.

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Old school magic meets the modern world in the epic adventure THE KID WHO WOULD BE KING. Alex (Ashbourne Serkis) thinks he's just another nobody, until he stumbles upon the mythical Sword in the Stone, Excalibur. Now, he must unite his friends and enemies into a band of knights and, together with the legendary wizard Merlin (Stewart), take on the wicked enchantress Morgana (Ferguson). With the future at stake, Alex must become the great leader he never dreamed he could be.

Helmed Cornish (Attack the Block), the children's film began principal photography in September 2017 in London. In addition to Ferguson, the cast also includes Patrick Stewart who plays Merlin's true form while his young disguise is portrayed by Angus Imrie.

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Written and directed by Joe Cornish, The Kid Who Would Be King stars Louis Ashbourne Serkis, Dean Chaumoo, Tom Taylor, Rhianna Dorris, Angus Imrie, with Rebecca Ferguson and Patrick Stewart. It is scheduled to be released on Jan. 25, 2019.