Worn by: Maximilian Schell as Dieter Frey
Reference: Omega Speedmaster
Brand: Omega
A movie about a British agent Charles Dobbs (played by James Mason), who's investigating a suicide case and discovers there's a lot more behind it. At some point, a straight-lug Speedmaster can be seen on the character of Dieter Frey (played by Maximilian Schell).
Source: https://www.fratellowatches.com/speedmaster-in-movies/