Tamil superstar Rajnikant is believed to have undergone minor plastic surgery at a private hospital here Tuesday.

The surgery on his lips was performed Tuesday morning, sources close to the actor said.

The hospital, however, has refused to comment on the matter.

Rajnikant checked himself into the hospital Monday night, the sources said.

The actor is planning a new film "Jaggubhai", almost three years after his last effort "Baba", which did not do well at the box office.

The PMK, part of Prime Minister Manmohan Singh's coalition government, had criticised Rajnikant, saying his films and characters were bad role models for the youth.

Rajnikanth and his fans were involved in a verbal battle with the PMK over this and the actor came out in support of the Bharatiya Janata Party-AIADMK alliance during the general election.

"Jaggubhai", however, has run into political trouble.

The film's subject, about a Muslim terrorist being reformed by a woman saint, has been criticised by the Tamil Nadu Muslim Munnetra Kazhagam (TMMK), a non-political outfit with some two million followers.

Urging director K.S. Ravikumar to stop making a film on these lines, TMMK president M.H. Jawahirullah has warned Rajnikant to change the way Muslims are portrayed in the movie or be prepared for large-scale opposition.