Panerai Luminor Marina PAM 351 - Ryan Reynolds - Selfless
The first spy shots of Ryan Reynolds on set reveal a watch that looks similar to a Panerai Luminor, with the protected crown as the only clearly visible unique element. The watch also seems to have a steel case and brown leather strap. The buckle can just be spotted as well, which seems to confirm this is a Panerai watch.
Update: in the film, the watch gets a good close-up, confirming this is a Panerai Luminor Marina PAM 351! The watch has a black dial, date window at 3 o'clock position and brown leather alligator strap.
Selfless is an unconventional sci-fi thriller about a terminally ill billionaire who buys a chance for eternal life through an experimental underground medical procedure called "shedding", which transfers his consciousness into the cadaver of a younger man. Photos of Ryan Reynolds driving in a Lamborghini Aventador show that Reynolds' character will enjoy the best of life, so his watch will probably match.