The actor – who is still best known for playing Neville Longbottom in Harry Potter - was among the star-studded crowd at a showing of The Mentalists at Wyndham's Theatre on Monday, 13 July.
And he made sure we all knew exactly what play he was going in to see by flashing the invite at the cameras!
Matthew, who turned 26 last month, was joined at the theatre by the likes of Kate Beckinsale, Stephen Merchant, Dara O'Briain and David Mitchell.
We'll next see Matthew on the big screen in romantic comedy Me Before You which stars fellow British actor Sam Claflin and Game of Thrones star Emilia Clarke.
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