Rumour mill: is Julia Roberts pregnant?

Julia Roberts sparked speculation she is expecting her fourth child after stepping out in Los Angeles with a noticeable bump concealed by a baggy sweater.

The 'August: Osage County' star was with her cameraman husband at his parents house at the time, according to gossip website TMZ.com.

The 46-year-old actress already has eight-year-old twins, Hazel and Finn, as well as a six-year-old son, Henry, with her husband of 11-years Danny Moder.

The actress recently opened up about juggling her career and her children, and joked that her agent is worried she will soon become a full-time mother.

She said: "As my career is slowing down, he thought, I've got to figure this out before she brings it all to a screeching halt in favour of car pools."

The Oscar-winning actress also revealed that she has no problem waiting for the right role to come up.

She explained: "The things that are correct for me will come to me at the time that I am interested in them and have the capacity, the understanding, to do them.

"When I miss out on a part, I can be bummed I didn't get it, but then I see who got it, and I think, 'Oh, well.' "

[comment] Roberts pictured on holiday in Co Mayo last year.[/comment]

Julia also previously said that she felt she had "earned" a break from Hollywood to start a family after almost two decades of acting.

She said: "I had been working for 18 years when I had Hazel and Finn almost nine years ago. So I felt like I earned that time in my house and in my kitchen and in bed all day with these two little people. I felt that was my present to myself."

She added: "I worked hard, and I was very devoted to that, and then I earned this jewel box of a life that I felt completely entitled to. It still is really important, but it has made me take more things into consideration.