The sound of wedding bells is getting closer for Justin Timberlake and Jessica Biel. The happy couple celebrated their engagement with a 100-deep posse.

Us Weekly reports that the guests wore all-black cocktail attire. Timberlake donned a black suit with a matching fedora, while Biel rocked a leopard print fitted dress with a hot pink belt and heels. Sounds cute, right?!

Guests included Timberlake's former 'NSYNC bandmates Lance Bass and J.C. Chasez, as well as TV hostess with the mostess Ellen Degeneres and actresses Portia De Rossi and Amy Adams. The party took place at the home of Timberlake's pal and design partner Estee Stanley.

A spy told Us, "Jessica and Justin were mingling both separately and together throughout the party. Jessica seems to be very close with Justin's friends and vice versa. You can see that they have been dating for a long time and really know each others friends and family well." We'd hope so, at least by now!

A source said, complete with champagne and Wolfgang Puck catered grub, "The party was a fun celebration and a preview of what's to come with the wedding." Sure sounds it!