As I mentioned, I've not yet seen Dharmendra's debut film, Dil Bhi Tera Hum Bhi Tere, so I can't really tell you much about it -- there is, however, an intriguing plot summary on IMDb.
I'm assuming Dharmendra plays Ashok, the cigarette seller who falls in love with with the maidservant and then gets hired as a boxer. It just sounds so....Dharmendra.
Also? I think that if I'd been of an age to be watching Dharmendra's films when he first started out? I'd be one of those women they tease about in Yamla Pagla Deewana, absolutely mad for him and sleeping with his photo under my pillow.