Leonard Nimoy explains why he couldn't resist returning to Fringe

Nobody expected Leonard Nimoy to return to Fringe the way he did last week — after all, the science fiction MVP had retired from acting. And the show had gone to crazy lengths to include his character, William Bell, without requiring his physical presence, including an animated episode and a "bodily possession" storyline.

On a conference call with reporters this morning, Nimoy explained just why he couldn't stay away from Fringe — and why he probably won't turn up in the new Star Trek movie, after all.

Spoilers ahead...

He was excited to play a villain
Nimoy kept talking about how much fun it was to play an evil version of William Bell, Walter Bishop's former friend and collaborator. Reading between the lines, he seemed to be hinting that he was bored with William Bell once it was revealed that Bell was actually a decent, trustworthy person in the tail end of season two.

Originally, said Nimoy, "the character of William Bell was supposed to be ambivalent," with a lot of mystery about whether he was a good guy or a bad guy. "We couldn't quite figure out what his motivation was." But after it was settled that Bell was basically a nice person, "the mystery of William Bell was explained," and it seemed like there was noplace to go with the character. But when he heard they were going to turn Bell into a baddie, it sounds like his excitement returned, because "I could play aspects of a character that I haven't played in a long time."

He's mostly identified with the "responsible" and "solid" Mr. Spock from Star Trek, so playing a villain, as he's doing here and in Transformers 3, has some appeal. He likes the "theatricality" of playing a villain — Nimoy used the word "theatricality" to describe his performance as Evil William Bell about a dozen times in the conference call. He also promised that we'll be stunned at the crazy things Bell gets up to in tomorrow night's season finale — Bell's gone out on a limb and is now prepared to do almost any horrible thing to get what he wants.

"You are going to see some bizarre activities from William Bell tomorrow night," Nimoy promised. "The character has become very exotic — exotic is the best way I can put it."

He loves Fringe

He stressed over and over again that he's not just interested in the character of William Bell — he loves this show, in general. The writers and producers of the show are "very bright," the characters are all "fleshed out considerably," and the cast is great. When he finished filming tomorrow night's episode, he told the Fringe cast that he was proud to be associated with them. "It's a superior company. I have never worked with a better company in my entire 60-year career."

He could be back next year

Nimoy absolutely would not rule out returning to Fringe for the final 13-episode season. "I'm a sucker for a good role," he said. "And J.J. Abrams, the executive producer of the show, is a friend of mine. He calls, I take his call." He also said he loves working with John Noble, and he's glad they've had more scenes together this time around. He'd love to work with him more, but it just depends on his schedule.

Meanwhile, though, he says he doesn't see any need to return for the new Star Trek movie as Spock Prime, as has been rumored widely. "My theory is, they don't need me. They've got a wonderful cast. Zachary Quinto has taken on the character of Spock and is well suited [to the role.] They've got a wonderful company of people. I don't think they need me." He noted the film has just finished shooting, so his window to be involved may already have closed.