NBCUniversal CEO Jeff Shell on Sunday left his role immediately after he admitted an “inappropriate relationship” with a woman in the comany, parent company Comcast announced.

“Today is my last day as CEO of NBCUniversal. 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,” Shell said in a statement.

Comcast hired outside counsel and began an internal investigation following a complaint. The complaint was filed by the woman with whom Shell said he had an “inappropriate relationship,” according to people familiar with the matter.

A company email said Shell’s team will report to Comcast President Mike Cavanagh. The company hasn’t been interviewing or searching for a replacement, and has no plans to do so immediately, said a person close to the matter. Shell, as well as other leaders at NBCUniversal, have already been reporting into Cavanagh for some time and he knows the business well, the person said.

“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,” Cavanagh and Comcast CEO Brian Roberts said in a separate statement.

Roberts will also get more involved with the NBCUniversal business alongside Cavanagh, the person said.

Shell, who is married, took over as CEO of NBCUniversal in January 2020. He oversaw the company’s theme parks, its Peacock streaming service, sports production operations, television stations group and entertainment and news television networks like NBC News.

Much of his time as CEO was shaped by the Covid pandemic, which forced the U.S. and much of the world to shut down weeks into his new position. During that time theme parks and movie theaters were shuttered, and the entertainment industry was upended as film and TV production shut down.

Shell, who succeeded Steve Burke, ushered in the launch of Peacock, NBCUniversal’s answer to the streaming wars. While Peacock was formulated under Burke, the streaming service grew and added more subscribers and content with Shell at the helm.

Just months after taking the CEO post, Shell reshaped NBCUniversal’s business and broke down the fiefdoms in the TV segment, with the aim of streaming and traditional TV working more closely together.

As part of the restructuring, layoffs took place that had been expected to affect less than 10% of the then-35,000 full-time employees. Cuts had been made across all of NBCUniversal’s business segments.

He had risen through the ranks of Comcast and NBCUniversal over the years.

One of his earliest roles was as president of Comcast’s programming group, where he managed national and regional TV networks, including E! He had also previously served as the chairman of NBCUniversal International, and later served as the chairman of the Universal Filmed Entertainment Group from 2013 to 2019. Before taking the helm as CEO, Shell was chairman of NBCUniversal Film and Entertainment.

Comcast is due to report earnings Thursday.

Disclosure: Comcast owns NBCUniversal, the parent company of CNBC.