Paramount is looking into claims Sylvester Stallone allegedly used disparaging language about background actors on the set of “Tulsa King,” which streams on Paramount+, sources told CNN.

The studio is investigating claims that first surfaced on social media in which Stallone was accused of referring to some performers working as extras on the set of the TV series as “ugly,” a “tub of lard” and a “fat guy with cane,” according to two sources close to the show.

“Bring in pretty young girls to be around me,” Stallone was accused of being overheard saying to the director of “Tulsa King” in another social media post about the set.

Both production sources told CNN that no formal complaints have been lodged against Stallone or the director. Human resources personnel became aware of the accusations from the social media posts, the individuals said.

Craig Zisk, the director and executive producer of “Tulsa King,” told TMZ “no such insults were hurled.”

CNN has reached out to representatives for Stallone and Zisk.

| Sylvester Stallone as Dwight "The General" Manfredi in "Tulsa King": Brian Douglas/Paramount+

The social media posts detailing the allegations appear to have originated on Facebook groups about background actor experiences on the set of “Tulsa King,” but were made more widely public when purported screenshots were shared on X, formerly known as Twitter, by television writer Julie Benson. Though she does not work on “Tulsa King,” Benson said she learned about the allegations from a friend who works as a background actor on the show.

On X, Benson also stated that a casting agent for the background actors quit working on the show, sharing a screenshot of an email that appears to be written by casting agent Rose Locke, who allegedly wrote, “I resigned because it was a clear toxic environment that I was not comfortable putting myself or background artists in.”

The sources also told CNN a casting agency resigned from the TV show.

A Facebook post on the official page of Locke’s company, Catrett Locke Casting, confirmed that it had “chosen to part ways” with “Tulsa King,” though the post did not specify why.

One source close to production on both seasons of “Tulsa King” told CNN that producers were aiming to match the same tone and feel of the background actors featured in the show’s first season and new actors for the second season were not what the director asked for from casting. The director asked the casting agent to send photos of the background actors, the individual added, which caused a rift and eventually the resignation of the casting company.

Additionally, some background actors were asking to take photos with Stallone on-set, this production source added.

The matter is now being investigated through interviews with cast and crew as production continues, according to both sources familiar with the current situation. Cameras recently began rolling on Season 2 of “Tulsa King” and the investigation is not altering production plans in any way, one source said.

Stallone and the director are continuing at work, as planned.

One production source told CNN that Paramount prides itself on a “fair and respectful workplace.” The other source, also familiar with the investigation, said that the matter is being taken seriously to ensure that everyone feels safe at work and is happy on-set.

CNN has reached out to SAG-AFTRA, which represents background actors, to ask whether the union has been made aware of - or is investigating - any of the claims surrounding “Tulsa King.” A representative for CSA, the Casting Society non-profit that represents over 1,000 professionals in the casting field, told CNN that casting directors for background actors are not covered in its membership.

101 Studios, the production company behind Paramount’s mega-hit “Yellowstone,” produces “Tulsa King” with MTV Entertainment Studios, which is owned by Paramount.

CNN has reached out to representatives for 101 Studios and Paramount for comment.