Allison Janney says 'Mom' producers were shocked when she showed up for the final season with short gray hair

• Allison Janney said that "Mom" producers were shocked to see her natural short gray hair.
• She said that producers were unaware her long blonde hair on the show was actually a wig.
• However, Janney added, now "everybody in the world knows" about her real hairdo.

Allison Janney said that "Mom" producers were shocked when they first saw her sporting a short gray hairdo - in fact, they might have even panicked a little.

During an appearance on "The Tonight Show" on Wednesday, Janney told host Jimmy Fallon that producers on the popular CBS sitcom had only ever seen her with long blonde locks (which is actually a wig) for seven seasons and were surprised when she showed up to film the eighth, and final, season with her natural gray hair.

"No one knew I was wearing a wig. And I come in for this season of 'Mom' and the producers see me like this," Janney told Fallon, gesturing at her hair. "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!'"

"And I'm like, 'Guys, I've been wearing a wig since season one, but nobody knew it,'" she continued. "But everybody in the world knows it now."

Janney previously said that being able to run her fingers through her short hair was "heaven-like" during an appearance on "The Drew Barrymore Show" earlier this month.

"I cannot tell you how amazing it is to feel free - free from hair color, and hair extensions, and hair tapes, and blah blah blah," Janney said.

"Hopefully, sometime, a man would be able to run his hands through my hair and appreciate it," she added.

Despite this new chapter in Janney's life where she's embracing her natural hair, Janney told Fallon that she's holding onto the blonde wig from "Mom" as a token of her time on the show.

Janney has starred on 'Mom' for 8 years

Janney won two Emmy Awards and two Critics' Choice Awards for portraying Bonnie Plunkett on "Mom." The show is airing its final season this year.

Plunkett's main character arc on the show centered around her recovery from alcohol and drug use and its impact on her relationships with those around her, specifically her daughter, Christy (played by Anna Faris).

Janney told Fallon that while wrapping the final season of "Mom," she went back and forth between being sad about having to say goodbye to the show and being happy about the next chapter of her life.

"It's so great when you get to entertain people but also put something out there in the world that helps destigmatize something like recovery and make it approachable to people," Janney said.