Meryl Streep never became a director because of her family.

The 62-year-old actress - who has four children with husband Don Gummer - admits she has been tempted to work behind the camera but decided it was too big a commitment and would mean missing out on a home life.

She said: "It's like being a grandmother: you go home at the end of the night.

"I used to think I'd like to direct but you know what? Honestly, if you have a big commitment at home you can't really do it. I have four children. While they were growing up it was really impossible. Directing is a big, big, big job.

"Acting, if you prepare, you can leave it on set and come back the next day. You can't do that with directing, it's like a 24-hour job."

While she hasn't directed herself, Meryl enjoys giving her input about her work and was delighted to be allowed to work closely with director Phyllida Lloyd on new movie 'The Iron Lady'.

She said: Usually I get a script, I say yes, we start shooting.

"For Example, I didn't have anything to do with how 'Mamma Mia!' evolved, whereas I did on this.

"I like directors that are interested in my input - even if it's outside my department. That's a pain in the ass for a lot of people I'm sure. But Phyllida welcomed it, so it was really, really gratifying to work on this in every phase of it."