Will Smith's 3D ear fear

Will Smith worried his ears would "take over" 'Men In Black 3'.

The actor had his first experience making a movie in 3D with the forthcoming sequel - in which he reprises his role as Agent J - and joked his biggest fear was that his already large features would be the main focal point of each scene.

He said: "This is my first time making a movie in 3D, I was just happy my ears didn't take over the whole frame. That was my big concern, that in 3D these things would be exponential!"

Will and his co-stars Josh Brolin and Tommy Lee Jones used a lot of ad-libbing when they worked together, and the actor says they spent time preparing what they wanted to say.

He added in an interview with website Flicks and Bits: "We do spend a lot of time before we get on the set coming up with things.

"When we're working a scene we will ad-lib the three or four days before we're actually in a scene. Coming up with things, trying things, and we'll have four or five different options of things we want to try.

"And if we get an inspiration on set we try to make it comfortable for one another to throw things in."