Megastar Amitabh Bachchan was recuperating and all his vital parameters were normal after a three-hour-long surgery at the Leelavati Hospital here on Wednesday night, authorities at the hospital said on Thursday, much to the relief of millions of his anxious fans.

The 63-year-old superstar was operated by a three-member team of doctors for treatment of 'diverticulitis of small intestine', a condition that causes inflammation and perforation of the small intestine.

Amitabh has been shifted to the intensive care unit (ICU) for post-operative recovery and his vital parameters were normal and is responding to treatment, they said.

"I have spoken to Amitabh...The worst is over...The diagnosis has been done and the treatment has also been done," Samajwadi Party leader, Amar Singh, a close friend of Amitabh, told reporters after visiting the ailing star on Thursday morning.

He said Amitabh has also thanked the media and the people at large for showing concern towards his health and extending wishes for a speedy recovery.

Sources said the superstar would take at least two-three weeks to recover and would remain out of action for a month.

Amitabh was shifted to Mumbai from Escorts hospital in Delhi on Monday night, after he complained of abdominal pain, which doctors at Delhi as well as Mumbai initially diagnosed as a suspected colitis.

After a series of tests that included CT scan, ultrasound and other investigations, doctors at Leelavati hospital had concluded that it could be 'diverticulitis of the small intestine.'

Sources said that it was a common ailment, which could be treated effectively with antibiotics and other medication.

However, in view of the near-fatal old injuries, which the megastar had sustained to intestines during the shooting of Hindi movie coolie in 1982 in Bangalore, doctors at Leelavati, after long meeting, decided to go in for a surgery.

Renowned gastrointereologist, P Jagannath and his team performed the three-hour-long operation and subsequently Amitabh was shifted to the ICU, where his condition is normal.

The surgery involved removal of tissues from the areas of intestine that had suffered injuries, hospital sources said, adding that histo-pathological tests are being performed on the tissue samples to confirm the present diagnosis.

The entire Bollywood expressed solidarity with the megastar, with many of the stars, directors and producers visiting Amitabh at the hospital in the past two days.

Prominent among them being actors Salman Khan, Sanjay Dutt, Tabu, Kiron Kher, Akshay Kumar, Dimple Kapadia, filmmakers Tinu Anand, Ram Gopal Varma and Madhur Bhandarkar.

Amitabh's close friends, industrialist Anil Ambani and chairman of Sahara Group Subrato Roy have been visiting the star to support the Bachchan family members.

Fans were also not left behind, with hundreds making a beeline out the hospital to extend wishes for Amitabh's recovery.