Paulygon,
From the clip, I'd guess that's it simply that in the film he has a very severe slicked-back style which exaggerates the hairloss, and in the interview he has it slightly messed up and brushed forward.
Of course, he could be using concealer in the interview as you say
It's amazing the effect different styles can have in creating an illusion of more/less hair.
I've a friend who for years slicked his hair back severely over his thinning crown. He finally got sick of wearing it like this and cut it very short. You'd swear he had gained hair!