Kannada matinee idol Rajkumar was admitted to a private hospital in Bangalore on Monday after he complained of breathing difficulty and chest pain early in the morning.
According to Wockhard Heart Institute, where he was admitted, the 77-year-old thespian's condition is stable.
"He is under observation in the ICU (intensive care unit). We have conducted some tests, and the reports are awaited," the actor's personal physician Ramana Rao told reporters at the hospital.
"He appears to be under stress. The death of his elder brother Vardaraj a fortnight ago has personally affected him," he said.
Rajkumar's family members are attending to him. The legendary celluloid hero has been ailing for sometime.
In 2000, Rajkumar survived a 108-day ordeal in the Satyamangalam forests of Karnataka after brigand Veerappan kidnapped him along the Karnataka-Tamil Nadu border.