The 28-year-old, who plays bisexual cross dresser Kris Fisher in the Channel 4 soap, has arranged for a Hollyoaks prize package to be auctioned off in aid of Northern Ireland's Children's Hospice.
The highest bidder will receive a behind-the-scenes tour of the teen soap's set at Lime Pictures in Liverpool, film a walk-on part for an episode, have lunch with the cast, spend the evening with McCarthy in a top Liverpool restaurant and spend the night in one of the city's famous hotels.
Speaking of the opportunity, McCarthy said: "I can't wait to meet the lucky bidder, work them on set and show them the showbiz hot spots of Liverpool. I am delighted that Hollyoaks have been able to support a brilliant event in my hometown for this very special cause."
The White Sapphire Ball takes place on October 3 in Belfast's Europa Hotel and will be hosted by Irish TV personalities Gloria Hunniford and John Daly. The evening will also feature a performance from the cast of Riverdance.
McCarthy added: "I only hope that I've got a good seat for this unforgettable Riverdance performance. To think that I've never seen Riverdance live and now I'll get the opportunity to see them perform at the Northern Irish Event of the Year!"