Class of '92 stars David Beckham, Paul Scholes, Nicky Butt, Ryan Giggs and Phil and Gary Neville arrived at the documentary's premiere at Leicester Square.
The former England captain attended the event with wife Victoria, and the couple's three sons Brooklyn, Romeo and Cruz.
When asked about reports that Beckham could become Sir David in the New Year Honours List, Styles replied: "Why not? He's a national treasure isn't he? It makes sense. I thought he was already."
More top news
IKEA is recalling almost 36 million chests and dressers in the US and Canada after the deaths of three children.
Toyota is recalling 1.43 million cars for an airbag inflator defect.
Prime Minister insists the UK will maintain a strong relationship with Europe especially on trade and security, even after it leaves the EU.