Sienna Miller would like to have more children.

The 'G.I. Joe: The Rise of Cobra' star is very happy with her boyfriend Lucas Zwirner and hasn't ruled out having a baby with him or getting married.

Speaking to the Metro newspaper's Guilty Pleasures column, she said: ''It is love. It's nice and settled and happy. Yes, I would love to have more children. I would love a daughter as well. I think I would be open to getting married, yes.''

Meanwhile, Sienna - who already has seven-year-old daughter Marlowe with her ex-partner Tom Sturridge - previously expressed her desire to have more kids and admits she wishes she had her daughter when she was younger.

She shared: ''I wish I'd had my daughter younger, and I could have grandchildren now. I'd like more children at my age now, too.

''There's something to be said for that dynamic. I was 30 when I had [my daughter]. It's a horrible facing of mortality. So, I'm all for young babies.''

The 37-year-old actress recently admitted she has an ''intense relationship'' with Marlowe and that they share a ''loving'' and ''beautiful'' bond.

Sienna said: ''My daughter challenges me and is a real mirror. When you have a child and you're raising a child you see aspects of your character in that person reflected back, it's the most loving, intense relationship that I have.

''There's nowhere to hide, she knows me I know her and that's a beautiful thing. She's really stubborn which is very like me, I see her as her own person but I see genetic things in her. She's heaven my kid.''