He is described as the Italian version of Michael Moore, but his attempt to launch a political career seems to have fallen flat.
The comic and provacateur Beppe Grillo has been refused membership of the main left-wing opposition party.
He had earlier created a storm when he said he wanted to stand as a candidate to lead the party, which has been struggling to tackle the lead of the Italian Right.
Pierluigi Bersani from the Partito Democratico party said: “A party cannot be a bus on which anybody can just jump on board to take a ride.”
Grillo is lauded by many as a breath of fresh air in his criticism of Italian politics, but he is dismissed by critics as a populist.
Even though he has been rejected as an opposition party member, Grillo says he will push ahead with his mission to become a politician.
In the past he has said that he wants to limit MPs to only two terms in ffice and ban anyone with a criminal conviction from standing for parliament.