Rosie O'Donnell is slamming Jay Leno over his past behavior toward a contestant on "The Biggest Loser."
On Tuesday, the 63-year-old comedian and actress took to Instagram to vent her frustration after watching the new Netflix docuseries "Fit for TV: The Reality of the Biggest Loser."
In one post, O'Donnell called out the 75-year-old former talk show host for his treatment of Season 8 competitor Tracey Yukich when she made an appearance on "The Tonight Show with Jay Leno" in 2009.
"jay leno is a mean a--hole #biggestloserdocumentary," O'Donnell wrote in the caption of her post, which featured screenshots from both the docuseries and "The Tonight Show."
The docuseries included an archival clip from Yukich's appearance on Leno's show, during which Leno read scathing comments and death threats directed at her that "The Biggest Loser" fans had submitted to the show via email.
In one comment, a viewer described Yukich as "just pure evil." Leno read an email from another fan, who wrote, "I would not step on the brake if I saw you cross the street. I want to accelerate."
"She wants to kill you, but she won't use a swear word," Leno told her.
In an interview that was included in episode three of the docuseries, Yukich cried as she recalled the experience.
"These are emails that people actually sent to the show," she said. "It was so bad. I was like, ‘Wow.’ My feelings were so hurt. They were. I didn't know that I was a villain until the show aired."
O'Donnell also blasted "The Biggest Loser" trainer Bob Harper in another post on Tuesday, writing, "ok now bob harper - can u not say IM SORRY - seriously- so hurtful- so cruel - come on bob - #biggestLOSERdoc @netflixuk."
In the post, she included screenshots from the docuseries featuring Harper and Season 7 contestant Joelle Gwynn.
Fox News Digital has reached out to representatives for Leno and Harper for comment.
During an interview on "Fit for TV," Harper defended his behavior toward the contestants.
"Always remember we were trying to make an entertaining show," he said. "What’s more important for weight loss? We all know it’s diet, but that becomes boring television."