The Glee actress is getting ready to celebrate alone, after boyfriend Cory was found dead in July.
Friends say they are worried about how the 27-year-old star will cope, especially as last year she was just returning from an intimate holiday with the late actor.
"Lea's dreading it. It was just before Christmas last year they went on a romantic skiing trip. They had an amazing time and that was when they first seriously talked about their plans to get married. When Lea joined her family that Christmas, she was so excited about her life with Cory.
"But now that all seems so long ago. She told us: 'I still can't believe he's not here.' All we can do is be there for her, but it'll feel all the more raw at Christmas. All she wants is for Cory to be with her," a Glee insider told British magazine Now.
As well as these upsetting Christmas memories, Lea is also bracing herself for the 100th celebratory episode of Glee.
Her character Rachel Berry enjoyed an on-screen relationship with Finn Hudson, the role Cory played in an example of life imitating art.
Cory was found dead in July of this year in a Vancouver hotel room, with coroners confirming he died from a mixed drug toxicity.
Lea has spent the last few months throwing herself into work commitments, and has her first solo album Louder coming out early next year.