Cheech and Chong are back, and they’re pitching “magic brownies” – for General Mills.

The stars of 1980s stoner comedies are featured in a funny promotion for Fiber One brownies, a new high-fiber snack targeted at aging baby boomers.

The online-only commercial resembles a movie trailer, and the twist comes at the end: the “magic” ingredient turns out to be fiber, not marijuana.

“Fiber – because now that you’re getting older, you need a new kind of magic from your brownies,” the announcer says.

Chong’s response: “This is the weirdest movie ever, man.”

The ad campaign began when the General Mills marketing team was brainstorming about the June launch of Fiber One brownies. When a New York ad agency, Modem, floated the magic brownie concept, “We loved the idea and that’s kind of where we started,” said Jim Wilson, a General Mills marketing manager.

Comedians Richard “Cheech” Marin and Tommy Chong were approached and agreed to the project. The pair’s stoner comedies include “Up in Smoke” in 1978, “Cheech and Chong’s Next Movie” in 1980 and “Nice Dreams” in 1981.

“We had to convince them, but we also had to convince General Mills,” Wilson said.

The Golden Valley-based foodmaker is famous as the wholesome home of Betty Crocker, the Pillsbury Doughboy and sports heroes on the Wheaties box. Strict internal policies bar advertising on programs with sexual content or excessive violence – even on reality shows where contestants eat bugs.

But the Fiber One magic brownie idea proved popular.

“People really resonated with it when we pitched it internally,” Wilson said. “A lot of those people are boomers, and they thought this could be really fun.”

For now, the campaign appears only in new-media channels.

“It’s online video, and it has some support with digital banner ads, and we have a microsite, and we did push it out on our Facebook page,” said General Mills spokeswoman Lisa Tomassen. “But we’re not doing a ton of outreach. We’re kind of throwing it out there, and seeing the power of viral.”

If the early reaction is any guide, the campaign is generating a lot of buzz. So General Mills may reconsider and build a larger campaign around Cheech and Chong.

“We’re still evaluating that,” Wilson said. “If it really takes off, then we would definitely be looking to see where we can take it next. Magic brownies 2.0.”

Tom Webb can be reached at 651-228-5428.

Watch the video at www.fiberone.com/magicbrownie/