Will Smith, who stars in his first movie in four years, Men in Black 3, has spoken about co-star Josh Brolin's "uncanny" depiction of a young Tommy Lee Jones.

"If you mess up Agent K, that's a little bit of a career assassination," Smith said.

"It was one of the most iconic duos of American cinematic history, but the first time he opened up his mouth on set, he got applause. It was such an uncanny portrayal, and he's actually not going to get credit because it's so perfect, it just goes away. By five minutes in, you're just watching a young Tommy Lee Jones."

The film is the third installment of the series, and follows Smith's character, Agent J, back in time to change history and stop an alien from assassinating his fellow alien monitor and partner, Agent K.

Smith joked that if aliens did exist, they would probably visit him first.

"I haven't met any yet and I hope not to, but if they show up they'll probably come to my house because of all those alien movies I made. They're going to think I know something."

Men in Black 3 opens on May 25.