The Will Mastin Trio started out as just Will Mastin and Sammy Davis, Sr., but then Sammy Davis, Jr. joined at the age of three, and the group was named the Will Mastin Trio.
The Will Mastin Trio (also Will Maston Trio on some bills) was a trio of dancers and singers formed by Will Mastin, Sammy Davis, Sr. and Sammy Davis, Jr..