So here goes.
Jimmy Stewart (1908 - 1997)
had one of his first screen credits in a film called "The Murder Man" (1935)
which also featured Lionel Atwill (1885 - 1946)
who's name, if you look closely, can be seen on this poster for 1939's "Hound of the Baskervilles"
He played Dr. Mortimer.
Lionel Atwill had appeared a least two other times previous with Basil Rathbone in other movies.
He was also with Rathbone in "Sherlock Holmes and the Secret Weapon."
Jimmy Stewart's connection came real early in his career.
Compliments of the Season!