New York, New York - NBCUniversal Chief Executive Jeff Shell is stepping down after three years in the top job due to "an inappropriate relationship," parent company Comcast announced.

Comcast in a statement said that it and Shell "mutually agreed" that he would depart effective immediately, following an investigation into inappropriate conduct led by an outside counsel.

"Today is my last day as CEO of NBCUniversal," Shell said in a statement. "I had an inappropriate relationship with a woman in the company, which I deeply regret. I’m truly sorry I let my Comcast and NBCUniversal colleagues down, they are the most talented people in the business and the opportunity to work with them the last 19 years has been a privilege."

Comcast does not plan to immediately start a search to find Shell’s successor.

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Instead, Comcast president Mike Cavanagh will take over Shell’s senior team and lead the entertainment company in the interim, Comcast chief executive Brian Roberts said in a note to employees. Nine executives, including Universal Pictures Chairwoman Donna Langley and entertainment networks chairman Frances Berwick, had reported to Shell.

"We are disappointed to share this news with you," Roberts and Cavanagh said in the note. "We built this company on a culture of integrity."

It was unclear how long Shell had been involved in the inappropriate relationship with the woman. Comcast said it acted "quickly" after launching the outside investigation.

The shake-up appears to have happened quite suddenly. Shell was involved in his regular duties all last week, according to sources familiar with the situation who were not authorized to comment, and he had traveled to Philadelphia this past Thursday, participating in festivities to honor Roberts.

Comcast executives declined to discuss the specifics or when they first received the complaint. Shell was not immediately available for comment.

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"Nothing is more important than how we treat each other," Roberts and Cavanagh said in the note. "You should count on your leaders to create a safe and respectful workplace. When our principles and policies are violated, we will always move quickly to take appropriate action, as we have done here."

NBCUniversal ousted longtime Universal studio executive Ron Meyer in August 2020 after learning he made hush money payments to a woman to cover up an old affair.

Last year, former NBCUniversal chief executive Jeff Zucker was also forced to resign from the top job at rival CNN after acknowledging an affair with his longtime communications chief.