Birthday surprise

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Across
  1. 3. : Sharp outfit (4)
  2. 5. : Legendary Milan theatre (2,5)
  3. 8. : Musical opener (8)
  4. 9. : Ends every week (7)
  5. 12. : Work in several acts (5)
  6. 14. : “Thus,” in Italian (4)
  7. 15. : Handout with cast list (9)
Down
  1. 1. : Gesture of affection (4)
  2. 2. : Tier of theatre seating (7)
  3. 4. : “All women,” in Italian (5)
  4. 6. : What this puzzle celebrates (4)
  5. 7. : Place for performance (5)
  6. 10. : Cry for more (6)
  7. 11. : Prodigy with an unfinished Requiem (6)
  8. 13. : Four-letter 'air' (4)