Fox’s executive panel at the TCA Press Tour was very late beginning this afternoon, but as Peter Rice (Chairman of Entertainment) and Kevin Reilly (President of Entertainment) took their seats, Rice assured the gathered group of television critics, “We have a good reason for keeping you waiting.”

He was right.

Minutes later, surprise guest Simon Cowell had stepped onto the stage, taken pen in hand, and officially signed the paperwork to bring his popular UK series, “The X Factor,” to Fox in 2011. He will serve as the show’s executive producer as well as a judge. There is, however, a down side to this development: it means that this will be Cowell’s final season as a judge on “American Idol.”

Prior to Cowell’s surprise arrival, Rice had acknowledged that Cowell’s future on Fox was directly connected to whether or not the network would pick up “The X Factor,” a series for which he has long established considerable passion.

“There has been a lot of speculation, partly because we didn’t have an an agreement,” said Cowell, after taking his seat. “We reached an agreement at about half past ten this morning.”

“More like half past eleven,” corrected Rice, with a laugh.

“I’ve always had a fantastic relationship with Fox,” Cowell continued. “We did talk about me staying on both shows, but then when we looked at the practicalities of that, it was just impossible. I made a commitment to staying on the show in the UK, and I didn’t think it was right for me to also do two shows in America. I can barely manage to do ‘American Idol’! We had a lot of discussions about it, a meeting with Peter in October, but it was done very gentlemanly, the whole thing.”

As far as Cowell’s departure from “American Idol,” he likens it to having a good player on a good football team: they work well together, but when the player retires, the team is still successful. In the end, it comes down to the fact that “American Idol” is not Cowell’s show, whereas “The X Factor” is.

“It’s still close to me,” he said, “and I made sure that ‘Idol’ would be protected. The show could last for ten or twenty more years. I’m confident that it will continue to be the #1 show, and everyone’s committed to keeping it that way.”

Rice described Cowell as “irreplaceable,” taking a pass on making any comment about who the network might be pursuing to fill his spot on the series while offering assurances that the network is fully aware of the necessity of maintaining the same level of energy for “American Idol.”