Freezing a cake before decorating?

[PaintedTshirt]

Ok so I'm making a cake for DD's party on Saturday. It's going to be a rainbow layered cake, covered in butter cream.

I'm sure I read that I can freeze the cake and decorate it while it's frozen?? Apparently it will stop crumbs getting stuck in the icing?
Can any experts tell me if this is true?

I'm having visions of the buttercream all going runny as the cake melts underneath

TIA!

Yes I do this all the time! I usually defrost it a bit and buttercream it and put it in the fridge overnight, I bring it back to room temperature before I cover it in fondant the next day.