Jeff Shell is out as NBCUniversal CEO (CMCSA) following a company investigation that found Shell had an "inappropriate relationship" with a female employee.

Comcast announced the news on Sunday afternoon — less than a week before it is set to report quarterly results. According to a joint statement, Comcast and Shell mutually agreed that the executive will depart effective immediately.

"Today is my last day as CEO of NBCUniversal," Shell said. "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," he continued.

Comcast shares opened relatively flat at the start of the trading week on Monday.

In an internal memo obtained by Yahoo Finance, Comcast CEO Brian Roberts and Comcast President Mike Cavanagh wrote to employees, "We are disappointed to share this news with you. We built this company on a culture of integrity. Nothing is more important than how we treat each other. 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."

"Please know that NBCUniversal is performing extremely well operationally and financially, and we couldn’t be more enthusiastic about our position and prospects going forward. We are fortunate to have an experienced, world-class group of executives leading this incredible company," they added.

Shell, who had been with Comcast since 2004, oversaw news and entertainment television networks, in addition to the company's film studio and theme parks divisions. He had served as NBCUniversal CEO since January 1, 2020 after succeeding Steve Burke.

Prior to the chief executive role, Shell was Chairman of NBCUniversal Film and Entertainment where he focused on content creation, including the programming and distribution behind NBCUniversal’s film and network television businesses.

No successor has been named at this point. Comcast reports Q1 earnings on Thursday, April 27.

Alexandra Canal is a Senior Reporter at Yahoo Finance. Follow her on Twitter @alliecanal8193 and email her at alexandra.canal@yahoofinance.com

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