Ellen Pompeo tweets support for Gabrielle Union after controversial 'AGT' exit: 'Stand with your sisters on the front lines'

Ellen Pompeo is speaking out in support of Gabrielle Union after the actress was reportedly fired from her judging position on "America's Got Talent" which she claims is because of her complaints about the show's culture.

Union, along with Julianne Hough, will not be not returning for the upcoming 15th season. She complained to NBC about what she said were several problematic situations on set, according to allegations made in a recent report from Variety.

In a series of tweets, the "Grey's Anatomy" actress supported Union for reportedly making complaints about issues involving everything from alleged racial discrimination on the show to comments on female hosts' appearances and more.

"I support @itsgabrielleu commitment to speaking up to injustice," she wrote. "It takes courage."

Pompeo urged her followers and Twitter users to take action in the face of injustice and intolerance.

"This is a teaching moment. It’s important..white girls I’m talking to you..whether you truly understand what racial injustice is or not..that you stand with your sisters on the front lines," she tweeted. "Don’t cut side deals & don’t not get involved because it isn’t your issue..because it is."

"Workplace cultures will continue to be toxic until there is unity and solidarity among all women," she wrote in another tweet. "If you go for self in these moments you undermine the work we are out here trying to do. Obviously this network feels like they can operate like this and it’s okay."

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One situation Union reportedly had an issue with, according to Variety, was said to have involved comedian Jay Leno. The former late-night television host reportedly joked that a painting featuring dogs on set in Simon Cowell's hallway was something you'd find “on the menu at a Korean restaurant."

Another incident allegedly involved a performer who impersonated Beyoncé and emerged with black hands. In both cases, neither alleged segment appeared on the show.

Additionally, Variety reports that Union and Hough often received “excessive notes” on their appearance -- allegedly noting that Union's frequently-changing hairstyle was reportedly “too black” for the "AGT" audience.

Judges Simon Cowell, Howie Mandel and host Terry Crews are all expected to return to the series.

Union has yet to publicly comment on the Variety report. NBC and series producer Fremantle issued a joint statement to ABC News on the report:

“‘America’s Got Talent’ has a long history of inclusivity and diversity in both our talent and the acts championed by the show," the statement said. "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.”

NBC, Fremantle and Syco Entertainment also released a follow-up statement on the report:

"We remain committed to ensuring a respectful workplace for all employees and take very seriously any questions about workplace culture," the statement said. "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."

A spokesperson for Jay Leno did not immediately respond to ABC News' request for comment.