By Jen Heger - Radar Assistant Managing Editor
As previously reported, Loeb popped the question to the stunning actress, in Mexico, while the actress was celebrating her 40th birthday.
“He popped the question while at the Mayan archeological ruins of Chichen Itza with the entire birthday entourage,” a source close to the couple previously told Radar. Sofia's Modern Family castmates Jesse Tyler Ferguson, Julie Bowen and Sarah Hyland were on hand for the festivities.
The surprise party will be held at a swanky mansion Saturday afternoon in the Hamptons.
"The party will be a surprise for Sofia and Nick's friend Pat is throwing it for the couple. It will be a celebratory party, and Nick is very much in love with Sofia," a source close to the situation told Radar.
The Columbian beauty and her aspiring politician fiance broke up earlier this year, but began dating again a short time later.
Vergara's rep released a statement earlier this week denying the reports, “As of today, Sofia is not engaged."
Looks like as of this weekend she will…. Officially!