ABC News' Michael Falcone reports:

One presidential candidate is buying television airtime in California, but it's not Mitt Romney or Barack Obama.

It's former sitcom star Roseanne Barr, who is running as the Peace and Freedom Party's presidential candidate.

Media tracking sources tell ABC News that Barr is spending $4,900 to run television ads in the San Francisco Bay Area from Oct. 9 through Oct. 16. She's purchased time on cable stations like CNN, MSNBC, TBS, the Country Music Channel and Comedy Central.

Solidly-Democratic California typically does not get much action on the TV airwaves from the major party presidential candidates.

No word yet on what the ad will look like, but here's a clue: Barr is running mostly on a one-issue campaign platform - legalizing marijuana.

"Thank you for breaking through your mind control programming and having some free thought," she told a crowd at an Oakland, California marijuana dispensary earlier this month. "Marijuana really does help you break through that and remember what is important."

And in an interview with the Bay Area television station, KTVU, she was candid about her own pot use: "I have a prescription and absolutely I do smoke marijuana and I have for several years, most of my life to this point."

Barr captured the Peace and Freedom Party's presidential nomination in August and chose anti-war activist Cindy Sheehan as her running mate. She originally competed for the Green Party nomination, but lost that bid.