Endemol, the Dutch-based television production company behind the hit Big Brother TV show, has parted company with its chief executive Joaquim Agut.
Big Brother is now in its seventh series in the UK
Although the firm said in a statement that Mr Agut had resigned for personal reasons, the news has renewed takeover speculation surrounding the group.
Reports have suggested in recent weeks that Endemol's parent firm, Spain's Telefonica, wants to sell the business.
A group of investment banks are said to be interested in buying Endemol.
Telefonica floated a 22.3% stake in Endemol on the Dutch stock market last November, leaving it with 75% ownership.
Endemol said on Thursday morning that it would seek to replace Mr Agut without delay.
Analyst Oskar Tijs said: "We have always expected Agut would resign if and when Telefonica gives up control over Endemol."
Telefonica gave Mr Agut, a Spaniard, the top job at Endemol two and a half years ago.
"The supervisory board and management board regret Mr Agut's decision, but respect it and thank him for his valuable contribution and achievements," said Endemol.
The company has sold its Big Brother concept to 37 countries around the world.
Endemol turned over £614m last year and income from Big Brother related activities is thought to make up almost 20% of this figure.