Sarah Michelle Gellar

’InStyle’ mag throws a party for Sarah Michelle Gellar and Freddie Prinze Jr. and more — and ET is there!

Hollywood’s hottest young celebs turned out for InStyle mag’s seventh annual "Summer Soiree" last night, and ET had exclusive access to the event!

Tinseltown’s best and brightest — including SARAH MICHELLE GELLAR and hubby FREDDIE PRINZE JR., JERI RYAN, MARG HELGENBERGER, ELISHA CUTHBERT and more — came out to celebrate the summer night at one of the hottest parties of the season.

Former "Buffy the Vampire Slayer" Sarah Michelle recently posed in a seductively sexy photo spread for the September issue of the mag, in its "What’s Sexy Now" feature.

And stars remembered the late, great MERV GRIFFIN, who will be laid to rest Friday in Beverly Hills.

KELSEY GRAMMER told ET, "I was a big fan of his. Ever since I found out he invented ’Jeopardy’ I’ve been trying to think of a game show, because apparently they’re very lucrative. He was a great guy; a singular Hollywood personality, but a warm, loving, wonderful kind of character."

And TIM DALY revealed, "I was on ’The Merv Griffin Show’ a million years ago when I was a kid, and I remember him being very kind to me. He had a fantastic life and he lived a long time. I’m sad that he’s gone, but he did pretty darn well. I would sign up for that right now."