ROME (Reuters) – Italy’s most famous chef and more than 80 actors, singers, directors and athletes on Sunday backed a constitutional change to be voted on in two weeks, giving Prime Minister Matteo Renzi desperately needed support.

Italians will vote in a Dec. 4 referendum over whether to accept Renzi’s flagship reform, which would drastically reduce the role of the Senate (upper house of parliament) and take powers back from regional governments.

While poll results cannot be published during the final 15 days ahead of the vote, surveys released before the Friday cutoff showed the “No” vote firmly ahead.

To try to turn the trend around, the 41-year-old Renzi continued his furious campaigning for a “Yes” vote on Sunday, repeating on a talk show that he does not intend to “scrape by” as prime minister if he loses.

Italian banking stocks fell to their lowest level in six weeks on Friday and bond yields rose for a fourth week on the prospect that a “No” vote may topple Renzi’s government and usher in a period of political instability.

Massimo Bottura, whose Osteria Francescana has three Michelin stars and was named the world’s best restaurant this year, told Italy’s most-read newspaper on Sunday that he may leave the country if the constitutional reform is defeated.

“If the ‘No’ wins I’ll be tempted to drop everything and move abroad,” said Bottura, whose restaurant is in Modena, Italy. If the logic that “in Italy things can’t get done” wins “then it’s all over,” he said in Corriere della Sera newspaper.

Separately, more than 80 well-known Italians signed a appeal in support of a “Yes” vote, saying that while Renzi’s reform is not perfect, it would help break gridlock in Rome.

Italian tenor Andrea Bocelli, Oscar-winning director Paolo Sorrentino, World Cup-winning soccer player Marco Tardelli and actor Luca Zingaretti were among those who signed the appeal.

“Actors, singers and dancers sign an appeal for a “Yes” vote … These are (Renzi’s) rich and wise ‘educators’,” Northern League party leader Matteo Salvini said.

Like all opposition party leaders, Salvini is campaigning for a “No” vote.