SIMON Cowell is at the "centre" of ongoing investigations into America's Got Talent and the allegations of a toxic work culture on set, according to US reports.
X Factor judge Cowell is now reportedly at the "centre" of the investigation as the network attempts to discover what happened during Union's one-season stint as a judge.
A spokesperson for NBC insisted their five-hour meeting with the actress "was candid and productive", although Cowell's behaviour was reportedly one of the major topics in conversation.
Gabrielle also tweeted: "We had a lengthy 5-hour, and what I thought to be, productive meeting yesterday. I was able to, again, express my unfiltered truth. I led with transparency and my desire and hope for real change."
Insiders close to the issue told that "the ball is in NBC’s court to see if they can get Cowell to agree to make some changes to the way things are done on the show".
It is thought that the next step in the process will see an independent investigator take over.
Reports first emerged on Tuesday alleging that "Gabrielle believes there is a toxicity that has become normalised at Talent".
The insider told Deadline: "She wants to help fix that, because she loved a lot of her time on the show last season, even with the issues with Simon and what have you.
"But she could never go back, even if they did a [180] and asked her to for another season — no."
At the end of America's Got Talent's 14th series, Union was axed alongside Hough.
NBC and series producer Fremantle said in a joint statement: “America’s Got Talent has a long history of inclusivity and diversity in both our talent and the acts championed by the show.
“The judging and host line-up has been regularly refreshed over the years and that is one of the reasons for AGT’s enduring popularity.
"NBC and the producers take any issues on set seriously.”
While Gabrielle and Julianne's contracts were not renewed, their fellow cast members Howie Mandel, Terry Crews and Simon Cowell are all expected to return to the next series.
Hough, 31, is also alleged to have received excessive critiques of her personal appearance including hair, make-up and wardrobe.
Insiders claimed this had a detrimental impact on her morale.
Hough has denied these reports.
Most read in TV & Showbiz
NBC, Fremantle and Syco released a joint statement on Sunday.
It said: "We remain committed to ensuring a respectful workplace for all employees and take very seriously any questions about workplace culture.
"We are working with Ms Union through her representatives to hear more about her concerns, following which we will take whatever next steps may be appropriate."
The Sun Online has contacted reps for Simon Cowell for comment.