Bollywood star Sanjay Dutt was set to return to jail Thursday to serve the remaining three-and-a-half years of his sentence for possessing illegal weapons, in a case linked to deadly bomb blasts in Mumbai 20 years ago.

The popular 53-year-old actor must surrender to authorities after India's top court dismissed a last-ditch plea for more time earlier this week.

Dutt was convicted in 2006 of possessing guns supplied by gangsters behind the 1993 bomb attacks that killed 257 people, but he was freed on bail after serving 18 months in prison.

In March this year the Supreme Court upheld Dutt's conviction but cut his jail term from six years to five.

A bench of the court on Tuesday refused to hear a plea of a film producer who sought more time for Dutt to surrender so he could complete two films that are still being shot.

Analysts estimate about 2.5 billion rupees ($45 million) are riding in Bollywood on the muscular star, who is best known for playing a mobster with a heart of gold in the "Munnabhai" series.

On Wednesday, Dutt withdrew another plea to give himself up in a different city, which he had made citing threats to his life.

Officials said Mumbai's Arthur Road jail had received an anonymous death threat targeting the actor, the Press Trust of India news agency reported.

"We have taken cognisance of the letter received three days ago and shall be providing adequate security to Sanjay Dutt," said a top officer of the jail, where he may be taken initially.

A string of Bollywood names visited Dutt's home in the trendy Bandra suburb on his last day of freedom, while a Hindu rightwing group also protested outside to demand he go to jail without any VIP treatment, reports said.

On Thursday morning, media gathered outside the residence amid a heavy police presence, as well as at the court in south Mumbai where Dutt must turn himself in.

The actor, whose parents were two of India's biggest stars, shot to fame in the 1980s in a string of action movies in which he performed his own stunts, earning him the nickname "Deadly Dutt".

The father-of-three, whose mother was Muslim and father Hindu, was acquitted in 2007 of more serious charges of conspiracy in the deadly blasts, which also wounded more than 700 people.

The attacks were seen as retaliation for religious riots in which mainly Muslims died after the razing of an old mosque at Ayodhya in Uttar Pradesh state.

Dutt was found guilty of possession of an automatic rifle and a pistol, which he insisted were only meant to protect his family amid the tense atmosphere in Mumbai following the mosque's destruction.

At a news conference following the hearing in March, Dutt wept as he declared himself "a shattered man" and some prominent figures have called for him to be pardoned.