Related Clues:
- Bud ... and Lou Costello
- Costello's crony
- Singer with instrument entertaining 'undreds of people?
- Instrument entertaining big time, as half of a double act
- MP's rating book, pushing boundaries
- "What is on second" speaker
- Costello's chum
- Half the "Who's on First?" team
- 'Who's on first' speaker
- Comedian Bud
- "Who's on first?" inquirer
- Rocker Elvis whose aim is true
- Major '40s box-office draw
- "Who's on First?" comic
- Elvis of music