US comedian Al Franken, known for his biting satire of the American right, has announced he will run for Senate.
Franken announced his bid on the final edition of his radio show
Franken, who won Emmys for his writing on Saturday Night Live, is seeking the Democratic nomination for the seat held by Minnesota Republican Norm Coleman.
"I'm not a professional politician. I know I'm going to make some mistakes," he said on his US radio show.
The 55-year-old is best known in the UK as the author of political satire Lies and the Lying Liars Who Tell Them.
The best-selling book landed Franken in court after Fox News claimed its subtitle, A Fair and Balance Look At The Right, infringed their trademark slogan, Fair and Balanced.
A judge dismissed the case, saying Fox's case was "wholly without merit" but the resulting publicity sent the book to number one on Amazon before it was even published.
Franken's announcement came on the final day of his talk radio show on Air America.
The decision was not unexpected, and rumours of his candidacy had been rife since he announced he was to end his broadcasting career last month.
"Minnesotans have a right to be sceptical about whether I'm ready for this challenge," he said in a video posted on his website.
"I want you to know: nothing means more to me than making government work better for the working families of this state."
Franken was born in New York City but grew up in a suburb of Minneapolis, Minnesota.
He graduated from Harvard University in 1973, and joined the writing staff of Saturday Night Live during its first season in 1975, remaining a fixture on the show well into the 1990s.
In 2005, Franken and his wife moved back to Minnesota, which was widely interpreted as laying the groundwork for a campaign.
He is expected to make his first public appearance as a candidate on Thursday.