They didn’t have to needle him to pierce his fake nipples.

Ahead of Tuesday’s premiere of the fifth season of FX’s “Fargo,” Jon Hamm shared some behind-the-scenes secrets about his character, North Dakota sheriff Roy Tillman.

“I had to have some very blue latex put on my nipples, and then they cast a resoundingly lifelike pair of nipples, which they then pierced and placed over my own nipples, and we shot said nipples,” Hamm, 52, explained as part of a premiere screening and panel discussion on Nov. 15, Variety reports.

“The crew doesn’t get enough credit, but there was a dedicated nippleologist,” he added.

Hamm said he was fine to wear the artificial accessory if that meant making showrunner Noah Hawley, 56, happy.

“Noah had a pretty great sense of who this character was, and I was on board with going on that journey with him. It was fun,” he said at the panel, according to The Hollywood Reporter.

Season 5 of “Fargo,” which will stream on Hulu, also stars Juno Temple, Jennifer Jason Leigh, Joe Keery and Lamorne Morris.

The Post has contacted Hamm reps for comment.

Off-screen, Hamm married his “Mad Men” co-star Anna Osceola, 35, in June after nearly three years of dating.

He has been booked to play Coach Carr in the film adaptation of Tina Fey’s “Mean Girls: The Musical,” which hits theaters on Jan. 12.