Allison Janney surprised 'Mom' producers with her gray hair

Allison Janney caused a stir when she showed up to the set of "Mom" with her natural short gray hair.

The Oscar winner, 61, arrived to the studio full of emotions, knowing she and her co-stars were about to begin shooting the CBS sitcom's final season. But the show's producers took one look at Janney's hair and panicked, she told "The Tonight Show" host Jimmy Fallon on Wednesday.

"I come in for this season of 'Mom' and the producers see me like this and they're like, 'What have you done?!' 'How are we gonna do... ?' 'You should have asked us before you did this to your hair!'"

The producers needn't have fretted — Janney's worn a wig on the show since it began.

"I'm like, 'Guys, I've been wearing a wig since season one,' but nobody knew it," she told Fallon, adding, "So, everybody in the world knows it now."

Janney intends to take the wig with her as a memento. She'll also take "a few pairs of sweatpants" to remember her character, Bonnie, who, she joked, "loved to be comfortable, as does Allison Janney."

The former "West Wing" star debuted her stunning new gray look after deciding to let her natural hair grow out during the pandemic.

"I was in Ohio for most of 2020," she said on "The Ellen DeGeneres Show" in February. "I started ... a big, healthy few inches of gray roots came in and I just decided I wanted to be free from hair color and hair extensions. So this is the most authentic ..."

Janney opened up about the ease of her new hairstyle earlier this month on "The Drew Barrymore Show."

"I cannot tell you how amazing it is to feel free," she said, mentioning again how glad she is to be rid of hair dye and extensions.

She added, "To be able to run my hands through my hair — and hopefully sometime a man will be able to run his hands through my hair and appreciate it, it's just heaven. I'm enjoying this new chapter in my hairdo world."