Kumar, a versatile actor, first made waves with his performance in 1936 with the film "Achhut Kanya".
"Dadamoni used to paint with water colours in the bathroom...in the nude, " said Patel, who along with the rest of the Ganguly (Ashok Kumar was the screen name for Kumudlal Kunjilal Ganguly) clan is celebrating the birth centenary of the legendary actor, who died at 90.
"Once Dadamoni was asked to exhibit his talent at a charity function, but he kept on refusing the offer. When we persisted and asked him why, he said he paints only when he is in the nude, " said Patel, distributing samples of Ashok Kumar water sketches to the media.
She also said the actor, who was the eldest of the actor trio of Kishore Kumar and Anup Kumar, also practiced homeopathy as philanthropy for nearly four decades.
"He has treated many people free of cost, " Patel said.
Ashok Kumar, in a career spanning five decades, acted in over 250 films, won four Filmfare awards and the Dada Saheb Phalke award -- India's highest award for cinematic excellence.