Prime Minister Narendra Modi on Tuesday greeted megastar Amitabh Bachchan on his 80th birthday.

"He is one of India's most remarkable film personalities who has enthralled and entertained audiences across generations. May he lead a long and healthy life," Modi said, wishing him a very happy birthday.

Even at 80, Bachchan is one of the busiest actors as he remains in demand in the Hindi film industry while continuing to spearhead the highly successful TV series 'Kaun Banega Crorepati' year after year.

Superstar Rajinikanth also greeted Big B on his 80th birthday.

"The legend.. someone who has inspired me always… the one true sensation and superhero of our glorious Indian film fraternity enters 80 .. happy birthday my dearest and most respected @SrBachchan Amitabh ji .. with lots of love and best regards always," tweeted Rajinikanth.

Former head coach of Indian cricket team, Ravi Shastri posted Bachchan's video on his Twitter handle.

"Here's wishing the ULTIMATE King of his craft and more a very happy 80th birthday. God bless @SrBachchan," Shastri tweeted.

Actress Nimrat Kaur also wished the legend a happy birthday on Twitter.

"Celebrating Mr. Amitabh Bachchan’s eight awe-inspiring decades today. Marvelling at the evergreen nature of an entire ecosystem he represents, akin to the mythical wish-fulfilling tree, Kalpavriksh," tweeted the actress.

"So grateful to witness and be working in the era that’s bookmarked by his life story. Thank you for being who you are Sir. And thank you for being relentlessly extraordinary. Happy Birthday @SrBachchan Sir," she said in another tweet.

"An inspiration to people across generations. To many more years of happiness and good health. Wishing you a very happy birthday @SrBachchan sir," Virat Kohli wished Big B in a tweet.

Celebrity chef Sanjeev Kapoor also whished Big B on the social media platform.

"Happy Birthday Big B @SrBachchan ! You are indeed an inspiration to all. Wishing you good health and glorious years ahead," said the chef in a tweeted.

Actress Raveena Tandon also took to Twitter to express her greetings for Big B.

"Happy happy Birthday and love ! @SrBachchan Sir! Wishing you Health ,Happiness, and love always . #legend will always be in awe , since then to now , no one was , or will ever be you!," she tweeted.