Mary quit the former BBC One show last year alongside hosts Mel Giedroyc and Sue Perkins when it was revealed GBBO would be moving channels.
However Paul stuck with the show and will follow the programme over to its new home this year.
Speaking to Radio Times this week, Mary said she would "stand by" Paul but confessed they disagreed about the show's future.
Mary explained: “I would always stand by him. Paul and I had our differences about what was important to us but he is a brilliant bread-maker and I admired him a lot.”
The legendary telly star went on to reveal she was never actually asked to join Bake Off on Channel 4.
Mary told the magazine: “Well, I avoided being asked. It was suggested what would happen if I did go to Channel 4; what I would get, the advantages.
“But I didn’t ever have a meeting with them. I’d made up my mind. To me it’s an honour to be on the BBC. I was brought up on it.”
It was confirmed last month that a full series of GBBO will air in 2017.
In 2016 news broke that Channel 4 had purchased the rights to the hit baking show in a multi-million pound, three-year deal.
However as part of the BBC's original contract, it had the power to enforce a one year wait before any other channel could air the show.
But the BBC has since waived this clause allowing the series to begin on Channel 4 later this year.
An insider told the BBC News: "We don't want to get in the way of them reinventing the programme.
"In this instance, we believe it would be undignified to have one public service broadcaster in a potential dispute with another and the associated costs for each party would ultimately come out of programming budgets.
"We don't believe in driving up costs in the public sector."