Bollywood superstar Amitabh Bachchan, who was admitted to hospital after he complained of abdominal pain, is showing "definite" improvement, said a spokesperson for Lilavati Hospital here Tuesday.

The medical team attending on Bachchan is pleased with his progress over the past four days. Amitabh was taken to hospital Saturday when he was celebrating his 66th birthday at his bungalow Pratiksha in Juhu.

"Bachchan is definitely improving and doctors are happy with his recovery. Any other news is rumour, " said Lilavati Hospital spokesperson Mohan Rajan in a press statement.

"Bachchan is also able to converse with his family members, all of whom are with him constantly, " he added.

The Big B has expressed his gratitude and said that he felt "most humbled" by the prayers and good wishes of his fans and well-wishers. However, there was no indication when Bachchan is likely to be discharged from the hospital.

Apart from his wife Jaya, daughter Shweta Nanda, son Abhishek and daughter-in-law Aishwarya Rai are present at the hospital.