Hilary Duff would be happy to unexpectedly get pregnant again.

The 25-year-old actress and singer - who has 13-month-old son Luca with her husband Mike Comrie - admits that although she would be a ''bit overwhelmed'', she wants her children to be really close in age and it would be a nice surprise.

She told UsMagazine.com: ''We don't really have any plans right now, but I think we'd be happy if it happened and maybe a bit overwhelmed.

''But it's not something I'm dying to rush into. I'm enjoying him [Luca] so much, and now that he's a year, I'm finally getting to have a life again. He'll go down at seven and then we can go out for dinner or go do something fun and he doesn't even know we're gone.

''I think with two kids that would be a little harder. But we also want to do right by him and give him a sibling not too far apart so they have a lot in common and can be really close.''

Hilary, who is guest-starring on the season finale of 'Two And A Half Men' alongside Ashton Kutcher as his party-loving girlfriend, credits her own mother for helping her to stay sane after Luca's birth because she was on a ''hormonal rollercoaster''.

She explained: ''She's been so great -- helping me with the baby, coming over when I need to take a nap or escape for a little bit. My husband is amazing, too. If I want to run out of the house for an hour to go work out or go meet a friend for lunch, I can. I think that's really important.''