Ashers Bakery has confirmed it is to take the gay cake discrimination case to the Supreme Court.
In October the Court of Appeal upheld a finding that the McArthur family, who run the firm, directly discriminated against customer Gareth Lee due to his sexuality when he ordered for a cake with a pro-gay marriage slogan.
The order was rejected and his money refunded.
On Wednesday, the Lord Chief Justice Sir Declan Morgan ruled that Northern Ireland Attorney General could not take the matter to the Supreme Court.
However, the legal avenue remained open to the family.
And on Thursday it was confirmed they would lodge an appeal with the Supreme Court.
Ashers is run by the McArthur family who are being backed in their legal battle by The Christian Institute.
In a statement, they said: "Ashers Baking Company will take the necessary legal steps to instigate a Supreme Court appeal on this crucially important matter as soon as possible and papers must be lodged early in the New Year."
The gay rights activist Gareth Lee sued after his order was declined at the company's Belfast city centre shop in May 2014.
Mr Lee had requested a cake depicting Sesame Street characters Bert and Ernie below the motto 'Support Gay Marriage' for an event to mark International Day Against Homophobia.
Bosses at the bakery refunded his money for the order because the message went against their Christian faith.
The family insist their problem was with the cake and not the customer.
But Mr Lee claimed he was left feeling like a lesser person.
Last year Belfast County Court held that the bakery had unlawfully discriminated against him on grounds of sexual orientation and religious belief or political opinion.
The firm was also ordered to pay £500 compensation to Mr Lee.
Lawyers for the McArthurs appealed the ruling, arguing it would have been sinful for them to complete the order.
Judges held that the company cannot provide a service that only reflects their own political or religious message in relation to sexual orientation.
Last week lawyers for the bakery were formally refused leave to appeal the verdict to the Supreme Court.
That decision meant that only the McArthur family could petition directly for a hearing in London.