Ryan Seacrest Explains Mysterious 'American Idol' Sign-Off on Series Finale

— -- When Ryan Seacrest said goodbye to fans of Fox's "American Idol" this week, he caused much speculation the show wasn't ending after all.

Seacrest, who hosted the singing competition for all of its 15 seasons, finished by uttering his famous phrase Thursday: "And one more time -- this is so tough -- we say to you from Hollywood, goodnight America."

Then he added mysteriously "for now."

Seacrest, 41, took to Twitter Friday to explain.

"I didn't want to say goodbye last night," he wrote. "Thank you for 15 amazing seasons #IdolFinale."

"Idol" creator Simon Fuller has hinted the show may get a second life.

"There will no doubt be another format or refinement or elevation of the format," he told Billboard. "Now I can actually revamp it and come up with a new version and we can look back on 15 seasons and think of some legitimate ways to allow people to enjoy them again, maybe adding another dimension to it."

Fuller, 55, said that includes working with Pulse, a company that can create "a virtual pop star."

"I've spent a whole lot of time thinking about this," he continued. "I've been waiting for the technology to be good enough to make it happen. We have the digital rights for Elvis Presley and we're building a virtual reality show around him."