The UK's highest court will this autumn consider a judgment against a Christian-owned bakers found to have breached equality laws by refusing to make a pro-gay marriage cake.
The Supreme Court has listed a two-day hearing for legal arguments for October.
A lower court ruled the refusal of family-run Ashers to make a cake iced with the slogan Support Gay Marriage in 2014 was discriminatory.
The order was placed at its Belfast shop by gay rights activist Gareth Lee.
Daniel McArthur, the general manager of Ashers, said: "The fact that the Supreme Court is willing to hear arguments is very encouraging and reflects the importance of the issues and the high-profile nature of the case."
The case against Ashers was taken by Mr Lee with support from Northern Ireland's Equality Commission.
The controversy first flared when Mr Lee, a member of the LGBT advocacy group Queer Space, ordered a cake featuring Sesame Street puppets Bert and Ernie for a private function marking International Day Against Homophobia.
He placed the order in person at Ashers' Belfast city centre branch in May 2014.
It was accepted and he paid in full but, two days later, the company called to say it could not proceed due to the message requested.
In the original court case, District Judge Isobel Brownlie ruled that religious beliefs could not dictate the law and ordered the firm to pay damages of £500.
Mounting an appeal, Ashers contended that it never had an issue with Mr Lee's sexuality, rather the message he was seeking to put on the cake.
The business said the slogan was inconsistent with their deeply-held religious beliefs.