Kelso learns TV lessons

Ashton Kutcher is happy "That 70s Show" was renewed -- but then it never even occurred to him that it wouldn't.

Ashton, who plays Michael Kelso on the show, thought ALL the Fox shows would be returning in the fall.

"I really didn't know anything about the business, so I kind of assumed that if they were making a TV show, and spending that much money to make a TV show, that it was gonna be on for a while," he told TV Guide.

"I didn't know that some shows only go a couple of episodes and get canned because I never really paid attention. The shows that I watched were good shows, and they stick around for a while. So I didn't really realize that shows get cancelled."

One of Ashton's co-stars, Laura Prepon (who plays Donna), said she's still learning about the television business, too.

"I had no idea there was so much to even getting picked up on the air," Laura told TV Guide. "We did our pilot, then we had to get picked up, and keep the ratings and all that stuff. I had no idea about any of that. This is the first big TV thing I've ever been on."

Ashton and Laura's jobs are safe for awhile. Fox has renewed "That 70s Show" for two more seasons.