Possible Clues:

• Pavarotti standard
• Beloved Italian song
• Italian tenor standard
• Pavarotti standard whose name means 'My Sunshine'
• Common Italian encore
• Song for which Pavarotti won a 1980 Grammy
• Tune for The Three Tenors
• Basis of Tony Martin's 'There's No Tomorrow'
• Song that provided the melody for Elvis's "It's Now or Never"
• Neapolitan song