1968 Rolex Datejust
Michael Caine was one really cool mod dude in the late 1960's and early 1970s. In 1971 Michael Caine starred in Get Carter where he wore his Rolex Datejust on a leather strap. In this image we see Michael Caine on the set of Deadfall, in 1968, and you see him hugging Giovanna Ralli, while sporting his Rolex Datejust on a leather strap.
It is interesting to note how the suite Michael Caine is wearing in the photo below looks exactly like what is popular today, along with his timeless Rolex ;-)