Timothée Chalamet took a razor to his mane … because he’s showing off a new look … and it’s a shaved head!!!

The actor debuted his new hairstyle Tuesday on Instagram Live … during a promotional spot for his new ping pong movie, “Marty Supreme.”

In the footage, Timothée is walking around with his shaved head … while wearing some “Marty Supreme” merch.

We saw Timothée and his girlfriend, Kylie Jenner, Monday night at the New York Film Festival … and he was wearing a baseball cap … and it looked like he might have buzzed off his hair.