His portrayal of the 'sexy' and 'young-at-heart' sexagenarian Sam in Karan Johar's 'Kabhi Alvida na Kehna', who believes in living life to the fullest and wears his heart on his sleeves has endeared him to the audiences across the country and abroad.

At a time, when most of his contemporaries in the film Industry like Dharmender, Shatrughan Sinha or Vinod Khanna have either gone into semi-retirement or seen largely in grandfatherly roles in films, it seems life on celluloid has just begun for Amitabh Bachchan.

His portrayal of Sam in 'Kabhi Alvida na Kehna' has been hailed by critics as unique in the history of Indian cinema with the youthful fervour and vibrancy infused into the character by the Bollywood superstar.

Trade analysts say audiences have fallen in love with the character of Sam played by Mr Bachchan who on the one hand, comes across as an incorrigible flirt while on the other he is also seen as an intensely emotional father whose heart bleeds when he sees his son's marriage breaking apart.

Critics feel the beautiful combination of joviality and frivolity with pathos in Big B's portrayal of Sam's character puts him in the league of the best of Hollywood actors.

His 'below-the-belt' comments in the film in presence of his son kept audiences, specially in the cities, laughing in the ailes, providing the much-needed comic relief in the otherwise serious film.

At the same time, his emotional scenes like the one where he feels crestfallen seeing his son's marriage break apart and the scene after the 'Rock and Roll Soniye' song where he suddenly gets emotional on watching his son and daughter-in-law (Rani Mukherjee) fighting make the audience's relate with character.

Observers say Amitabh's portrayal of the character of Sam in 'Kabhi Alvida na Kehna' is first of its kind in the history of Bollywood. In fact, Shahrukh Khan is said to have commented recently that he wished he would also get to play a character like Sam when he is 60.

In fact, they say that of all the characters in the film, Amitabh's is the most endearing, apart from that of Abhishek Bachchan.