Justin Timberlake and Jessica Biel's Engagement Party

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On Saturday Justin Timberlake and Jessica Biel attended a cocktail party thrown by Biel’s stylist to celebrate their engagement.

The stylist, Estee Stanley, threw the party at her LA home. The 100-strong guest list was filled with stars including Ellen DeGeneres, Amy Adams, Lance Bass, JC Chasez, Timbaland and Jessica’s parents, Kimberly and Jonathan.

A source told PEOPLE that the happy couple arrived at the party looking very excited. Jessica chose to wear a long dress with hair down and looked stunning. Estee, the source said, created a warm, welcoming and festive party for the soon-to-be-wedded couple.

There was some live music, after which a deejay took over. Guests then danced to popular hits including Madonna’s “Holiday,” Michael Jackson’s “Good Times,” Whitney Houston’s “I Wanna Dance with Somebody” and Usher’s “OMG.”

Justin and Jessica danced and looked very happy, the source continued. Afterward, it was time for speeches and the source revealed that Justin was especially touched by Timbaland’s remarks. It was obvious they have a very special friendship.