Nicole and Adam, aka DJ AM, had an engagement party this weekend in Beverly Hills. Perhaps that is one of the reasons Lindsay made sure she was in LA while on break from filming. She is in the wedding party so I'm sure she did not want to miss this celebration. Also there to celebrate was Nicky Hilton but obviously not with her sister. Paris and Nicole are still not speaking to each other.
Thanks to People for the pic of Nicole, Adam, and her parents, Lionel and Brenda Richie (no longer married, but on friendly terms for their daughter sake). No word on if the party was filmed to be included in the Simple Life 4 which may be based on Nicole's wedding planning.