Mommy or Daddy has to have the Champagne gene. However, mommy could have it and it would be hard to tell since she's a double dilute or perhaps she's masquerading as a double dilute because of the Champagne gene (have you had her tested?).
I'm not well versed in Champagne genes either but read up on them here (I tend to take everyone's new babies as an excuse to brush up on my basic genetics):
Basically what they say is it's not uncommon for the newborn's coat to be darker than you'd expect, that they'll be born with blue eyes that will likely change to green/amber, and that the skin will initially be pink and darken with age.