Funny Video of Sammy Davis, Jr. Impersonating
Nat King Cole as They Sing a Duet

Sammy was terrific at doing impressions and this is proof positive, in fact he was good actor despite having no formal training, which was also true of his singing, dancing and playing instruments.  Read Sammy Davis, Jr.: Me and My Shadow by Arthur Silber, Jr. to know the man behind the legend.