The "Ocean's Thirteen" actor is "impervious to poo, snot, urine and vomit", and he has no plans to shirk his parental responsibilities, even if it kills him.

"They're trying to kill us! They really are," the star of upcoming film, "The Curious Case of Benjamin Button" joked with Oprah on "The Oprah Winfrey Show" on Wednesday.

"We'll get them to bed and one will show up about a half hour later. I know they've got shifts, they got it worked out."

He said: "I'm tough as nails. I'm impervious to poo, snot, urine, vomit. You can't get me. You cannot break me down."

Brad, 44, also revealed he and Angelina don't often take their brood shopping because it is such a struggle to get everyone organised.

He added to US TV talk show host Oprah Winfrey in an interview which will air today : "We don't go to the mall. It's like a half-an-hour just to get everyone buckled in and make sure they've got their snacks, and Zahara has got a blanket and Shiloh's got her silky.

"Angelina is militant about it. She's right on top of it. Thank God, because I'm always forgetting something!"

Meanwhile, Angelina has revealed she only breastfed her four-month-old twins Knox Leon and Vivienne Marcheline for the first three months because she struggled to cope with feeding the babies simultaneously.

She said: "You think, 'Ah, if anybody can do that, I can do that.' There's this football hold - it's a lot harder than it looks in the books. I did that a few times. I would take turns. It just takes a long time."