Possible Clues:

• Festive occasion attended by second pair of sexy stars
• Spiral, elliptical, group of stars
• Large group of notables and unknowns attending festivity
• Astronomical study
• Homosexual admits showing scant regard for morals in mutually attracted group
• Assembly of stars
• Many stars party and kiss everybody at the end
• Andromeda, e.g
• Couple of unknowns introduced by party host
• Unknown duo follow festival that hosts many stars