Raj Kapoor died on June 2, 1988 at the age of 63.
"Raj Kapoor. My Father. 1924-1988. Adieu, 28 years back! Achieved what most yearn in a life time. So proud to be his son!" Rishi wrote on Twitter.
The 63-year-old actor also changed his Twitter handle to "rahenge sada" which is the lyrics of a famous Raj Kapoor song "Jeena Yaha Marna Yaha" from the film "Mera Naam Joker".
Raj Kapoor, known as the "Showman of Hindi cinema", has starred in films including "Awara", "Shree 420", "Boot Polish", "Sangam" among others.