Possible Clues:

• When Juliet says 'Parting is such sweet sorrow'
• When Romeo marries Juliet
• When Hamlet says "Words, words, words"
• Play center, often
• When Bloody Mary sings "Happy Talk"
• When Musetta's waltz is heard in 'La Bohème'
• Pop Secret rival
• When 'light through yonder window breaks' in 'Romeo and Juliet'
• Second half of a musical, often
• When Hamlet says 'The play's the thing' in 'Hamlet'