Gary, who plays Dino Doyle in BBC comedy Mrs Brown's Boys, will join his wife, Sharon, and Radio Clyde DJ Romeo for a Halloween Ball to raise money for the Donna Mortimer Ballantyne Charitable Trust.
Tomorrow night's event at the Crowne Plaza Hotel will include entertainment by singers Mary Mac and Nina Nesbitt, as well as live dance music.
The Trust is raising cash to build the Kilbryde Hospice, East Kilbride.
Donna died of melanoma, the most dangerous form of skin cancer, in June last year. She was 39.
She had raised more than £1million for cancer charities after her diagnosis in 2002.
Tickets for tomorrow's event, which cost £80, are available from www.srgevents.com