His secret? 

Baby wipes, reports People magazine. 

Pitt offered this exclusive hygiene secret when he smelled Inglourious Basterds co-star Eli Roth during a close-up shot on set.

When Roth complained that he hadn't had time to bathe, Pitt countered, "I got six kids. All you've got to do is just take [the baby wipes], a couple quick wipes under the pits. Man, I'm getting [peed] on all day. I don't have time to take a shower".

Pitt told his Inglourious Basterds costar Eli Roth.

 "Man, I'm getting [peed] on all day. I don't have time to take a shower," said Pitt after Roth told him he didn't have time to take a shower.  

Good thing Brad has his baby wipes to keep him clean.

Brad has helped one celebrity in need—we're hoping Pattinson's next.