Charlize Theron thinks too much focus has been put on her weight gain for 'Tully'.

The Academy Award-winning star gained 50 pounds for her starring role in the new drama movie, in which her character is pregnant with her third child, but Charlize believes that the issue has been overblown.

She explained: ''Women gain that amount, if not more, every time they get pregnant. So it's not that big of a deal.

''I was playing this woman and I wanted to get closer to her. I don't think when an actress does that we have to get so focused on it.''

'Tully' has been described by some critics as 'Mary Poppins' for millennials.

And Charlize, 42 - who has two adopted children, a boy and a girl - has been intrigued by how women who don't have children have reacted to the Jason Reitman-directed film.

In the film, Charlize's character forms a strong bond with Tully, the woman she's employed to take care of her children.

She told Time Out London magazine: ''It's been really interesting to see young women who don't have kids being incredibly moved by this story. Because there's something of a Tully experience too.

''Younger women see this movie through the eyes of Tully: What will my life be like? Who will I marry? Am I going to be happy?

''Everybody can relate to that time where they have to say goodbye to a piece of themselves to make room for the next chapter. That's ultimately what Marlo's story is about.''