Conversation so far:
were Atomic Kitten all present for the reunion?
Frost had been involved in the early meetings to reform the group, but decided to focus on her pregnancy and was not involved in the reunion.
What songs did they perform at the reunion?
Right Now", "The Tide Is High (Get the Feeling)", and "Whole Again".
Did they release a new album during this time?
Atomic Kitten recorded their first new material in ten years when, along with the other groups from the show, they recorded a Christmas charity single.
Did the single sell a lot of copies?
Christmas charity single for Text Santa, a cover of Wizzard's "I Wish It Could Be Christmas Everyday".
The song peaked at number 13 in the UK.
What did it top in the US?
CANNOTANSWER.
Did they perform with other artists?
The Big Reunion, along with five other pop groups of their time: 911, Honeyz, B*Witched, Five and Liberty X.
were there any other albums during this time?
"I Wish It Could Be Christmas Everyday".
The song peaked at number 13 in the UK.

Question: what year was this?
Self-contained rewrite: What year did the Atomic Kitten single "Christmas Everyday" peak at number 13 on the U.K. album charts?