The balding Die Hard actor made Late Show host David Letterman chuckle as he sauntered out on set with a bright red hairpiece he claimed was made from "100 per cent" pure beef.
He said, "This is all natural. It's a meat hairpiece inspired by... who's that crazy lady? ...Lady Gaga!"
Willis kept up the prank as Letterman continued to question the unusual choice of toupee.
He joked, "Let me tell you, (this took) hours to get ready. It's 100 per cent ground beef sirloin. Top shelf, organic.
"Showering? Not a problem. I took a shower a couple (of) hours ago... lather, rinse, repeat. Tenderise."
The cheeky star then proceeded to shake salt and pepper onto his head to flavour the 'meat' before inviting a hesitant Letterman to dig in. The presenter took a forkful of the beef and shovelled it into his mouth, before having to walk offstage to spit out the food, much to Willis' amusement.
But Willis, who also joked about his past as a wizard during his interview, soon showed the TV audience it was all just for a laugh - as he whipped off the fake meat toupee and threw it on the floor.
Gaga drew gasps and stares when she wore her meat ensemble to the MTV Video Music Awards last month (Sep10) in a bid to prove she is "not a piece of meat".