In case you hadn't heard yet, LeAnn Rimes has a big rock on her finger given to her by fiancé Eddie Cibrian, and to celebrate their engagement, they flew to Cabo San Lucas, Mexico after Christmas.  But according to E! Online, all was not well, as they were reportedly left off the guest list at a star-studded party on Dec. 30.

Sources say Rimes and Cibrian wanted to go to a birthday bash hosted by Michael Meldman, the billionaire ex-boyfriend of Cibrian's ex-wife, Brandi Glanville -- and though Rimes and Cibrian were staying at a friend's home in the billion-dollar resort El Dorado (which Meldman owns), the newly engaged couple wasn't welcome at Meldman's party.  When they tried to get in, he said no because of his allegiance to Glanville.

Not to be left out in the cold,  Rimes and Cibrian took their party to Cabo's Pink Kitty, where sources say they were the “honored guests" being served by Pink Kitty's all female staff.

It was the first time for many to see Rimes' 5-carat oval diamond and platinum engagement ring, which features single cut pave diamonds and tiny rose cut diamonds set in a rose gold fleur-de-lis. Jeweler Brent Polacheck crafted the ring, and he just happens to be the childhood friend of Cibrian. Rimes and Cibrian both helped design the ring, as they wanted a new ring with an antique feel to it.