Name the celebrated actor who played the leading role in the first production of John Osborne’s The Entertainer (1957).

The correct option is Laurence Olivier.

The Entertainer is a landmark play written by the English playwright John Osborne, first produced in 1957. The play tells the story of Archie Rice, a failing music hall performer, which serves as a metaphor for the decline of the British Empire.
The legendary actor who famously played the leading role of Archie Rice in this original Royal Court Theatre production (and its subsequent film adaptation in 1960) was Laurence Olivier. Olivier's performance is widely celebrated as one of the defining roles of his career, bridging the gap between classical theatre and the emerging "Angry Young Men" movement of 1950s British drama.