The 'Transformers' actress - who has been dating actor Brian Austin Green on and off since they met in 2003 - had an argument with him after they were unable to agree on their festive holiday plans.A source is quoted by website Absolute Now as saying: "Basically, Megan wanted it all her way with Brian joining her and her friends and family for the holiday but Brian isn't so keen.
"He is very loyal to his family and thought they would at least share the holidays between the two. It's all ended in another tiff which means they probably won't see each other at all over Christmas."
The 23-year-old actress might not yet know where she is going to spend Christmas, but she recently revealed she's already got Brian's present.
The 'Jennifer's Body' star was searching auction website eBay with her lover when she came across a classic red 1966 Mustang Fastback at a bargain price, although the vehicle needed a lot of repairs.
She said: "We were going through cars on eBay and I found one in really good condition that was beautiful and for a good price."
