The youth went down on his knees, looked at the Bollywood beauty and asked: "Will you marry me?"
Deepika, who was accompanied by her co-star Neil Nitin Mukesh, seemed baffled by the sudden, unexpected proposal. But she was quick to respond.
"I am not ready for marriage yet, " replied Deepika, who looked lovely in a sari.
But the youth wasn't willing to give up so easily.
"But I am ready for you, " he said.
Deepika, who is rumoured to be dating liquor baron Vijay Mallya's son Siddharth, brushed the whole incident with a laugh.
Both the actors were in a fun mood and mingled with the huge crowd that had gathered in the south Delhi mall to catch a glimpse of the stars at the event organised by DT Cinemas.
Neil's father, singer Nitin Mukesh, was present at the event and he sang his father Mukesh's evergreen song "Kisiki muskurahaton pe..." for the crowd.
Even Neil and Deepika gave in to the requests of their fans by doing a casual dance to "Dhatad tatad", a popular song from "Lafangey Parindey", which releases Friday.
The film will have Neil playing a boxer who fights blindfolded, and Deepika will be seen as a visually challenged girl who can dance on skates.