Credit: Alberto E. Rodriguez/Getty Images; Noel Vasquez/FilmMagic

Filming a steamy sex scene with Dancing With the Stars finalist Gilles Marini wouldn't normally be considered an act of "cruelty."

But Brothers & Sisters star Rachel Griffiths laments she had to do it just six months after giving birth to daughter Clementine.

"I've got these lovemaking scenes with Gilles, and I said, 'I'm going to call PETA because it must be cruelty to animals to have a woman who just had a baby six months ago to have to do a bed scene with Gilles," she joked to at the VIP Opening Night of Art Los Angeles Contemporary in L.A. Thursday.

She added, laughing: "It's ridiculous!"

The 41-year-old actress -- who is also mother to son Banjo Patrick, 6, and daughter Adelaide Rose, 4 -- maintained modesty about how she has gotten her slim post-baby bod.

"I think it's just three kids and working full time," the Australian-born star told Us. "Honestly, I haven't thought about it. Really, I think I looked in the mirror at that moment and said, 'Oh wow! Maybe I should start working out.' But I tend to not get neurotic about it so I can meet my family's needs and my baby's needs. But, I am starting to feel like I want to get a little stronger and fitter."

As for Clementine?

"She's great," she told Us. "She's not crawling yet, but she appeared to be doing downward dog yesterday, which I was pretty impressed with!"