The Avengers star Mark Ruffalo and his wife faced a last-minute dash to name their first-born because they couldn't decide what to call him.

The Hulk admits he has procrastinated about naming each of his three kids for weeks after they were born, but his son Keen was almost saddled with the name Baby Boy Ruffalo.

The actor tells Men's Journal magazine, "We had a lot of names picked out, but when Keen was born, we took one look at him and said, 'None of those fit'. For the first two weeks we tried a new name every day.

"Then, after two weeks, we got a phone call from the Department of Records: 'Hey, you haven't picked out a name for your kid! You have until 12 o'clock today, otherwise his name is going down as Baby Boy Ruffalo - and it's really hard to change.'"

The actor reached for a dictionary, flipped to the 'K' section and stumbled across the word 'keen'.

His son Keen is now 11.