MUMBAI: Bollywood legend Amitabh Bachchan, who turned 66 on Saturday, was undergoing medical tests after complaining of abdominal cramps, a hospital spokesman said, as fans feared for his health.

“He has stomach pain and is undergoing tests,” Mohan Rajan, from Mumbai’s Lilavati Hospital, told AFP by telephone.

He described the actor’s condition as “stable” but could not confirm one report that he had an incisional hernia.

“We are giving him the best possible treatment. We understand the importance of Mr. Bachchan and his value to the nation,” he added.

Bachchan, who has superstar status in India, left his home in the northern Mumbai suburb of Juhu with his actor son, Abhishek, and daughter-in-law Aishwarya Rai, in an ambulance at lunchtime, an AFP photographer said.

Huge crowds that had gathered outside his house to wish him happy birthday anxiously watched him leave, television pictures showed.

Bachchan, wearing a brown-coloured woollen cap and blue ensemble, was spotted lying down inside the vehicle before being supported by Abhishek and another man as he walked into Nanavati Hospital, the photographer said.

The film star’s secretary, Sunil Doshi, told the Times Now television channel that Bachchan “developed some kind of stomach cramp” overnight, was taken for a CT scan and other tests and was now under observation.

Bachchan was later transferred to the Lilavati Hospital where he previously spent three weeks, including one in intensive care, after bowel surgery in November 2005.

He also suffered a severe stomach injury in 1982 while shooting the film “Coolie”.

With a career spanning four decades in India’s movie industry, doctors have warned Bachchan to slow down.

Hundreds of fans flocked to Bachchan’s personal website to wish him a speedy recovery.

One wrote: “Sorry to hear you are unwell and in hospital. We pray it is not serious. We pray for your wellbeing. Please slow down and take it a bit slower, I wonder how much toll your aggressive routine takes on your body.”

Bachchan, known as “The Big B” with a distinctive white beard, flowing grey hair and baritone voice, was last seen in his first English-language movie, “The Last Lear”, and has been on a world tour with his family.

Indian newspapers marked Bachchan’s birthday Saturday with a series of interviews. The Bombay Times commented that he had “never looked better. Or fitter” when they spoke to him two days ago on a film shoot.

“I enjoy being alive, I look for a new struggle, a new experience every day. An artiste has no right to say he is satisfied, that’s being defeatist,” he was quoted as saying.