Besides Sagar, in his mid 20s, his assistant Vishvanath Reddy was also killed and another person injured when their car rammed into a bridge near Tumkur, about 100 km from here, District SP T R Suresh told PTI.
The condition of the injured, admitted to a Tumukr hospital, was critical, he said.
Sagar was on his way to Bangalore from Pune when the accident took place around 6.30 am, Suresh said.
Reddy was driving the car.
A native of Bangalore, Sagar made his debut in Telegu film 'Ullasanga Utsahanga' which was a major hit in 2008.
Sagar's father B P Somu is a big time producer in Kannada films.
The young star had also acted in Kannada flick "Mr Premikudu" which was produced by his father.
He also did the lead in "Ayyo Pavam", Malayalam remake of "Ullasanga Utsahanga".