Speaking to the Press Trust of India, the actor was responding to the highly positive reaction received by Rishi Kapoor for his performance in Karan Johar's Agneepath.
"I am hearing such amazing stuff about my father's performance in Agneepath," said Ranbir.
"He is a brilliant actor. If a person is a good actor, then the person will continue to work lifelong and keep giving good performances. He is 55 plus, but he is still getting so of much of work to do."
The veteran actor plays a negative role in the film as Rauf Lala, a character first portrayed by Danny Dezongpa in the 1990s classic.
"There is some sort of childishness (in him) when he gets offers for any movie or any new character. His passion for work... for cinema inspires me to do better work," added Ranbir.
While the father-son duo have been seen together in a commercial for a soft drink, the Rockstar actor says there are as yet no plans for them to appear in a film together.
"No one has really offered us a script that both of us liked," he explained. "We both are individual actors and if a good script, good characters come our way and we both like it, then we will definitely work together."
Agneepath has broken all recent first day opening box office records.