Herbert Marshall, who plays a British army officer in World War I, actually served in that war and lost a leg in combat.
The role of Alan Trent was originally intended for Leslie Howard, who was having an affair with Merle Oberon at the time. When the affair ended, Howard dropped out of the production and Fredric March replaced him - much to the disgust of director Sidney Franklin, who thought Oberon wouldn't draw audiences without Howard as her co-star.
Lux Radio Theatre version starring Merle Oberon, Herbert Marshall, and Rod La Rocque aired June 22, 1936. In the radio version, Marshall played the role of Alan Trent instead of his film role of Gerald Shannon. La Rocque was married to Vilma Bánky, who starred in the original 1925 version of the film.
By their uniform cuff insignia, Alan is a lieutenant and Gerald is a captain in the British Army. Their unit is either the 7th Royal Fusiliers or the Grenadier Guards.
"The Screen Guild Theater" broadcast a 30-minute radio adaptation of the movie on May 8, 1944 with Merle Oberon reprising her film role.