Possible Clues:

• 'Love Is All Around,' to 'The Mary Tyler Moore Show,' e.g
• Subject to relative finally writing signature tune
• Air show has them for one hugging boy
• That elementary particle finally revealing signature in air
• Seem upset wearing G-string for such a melody
• Track particle drunk by the gallon
• 'My Heart Will Go On,' for 'Titanic'
• 'Where You Lead,' for 'Gilmore Girls'
• Musical calling card
• Show opener, often