The flamboyant Brazilian-born singer, who lives in the Black Country, will be playing the Wizard of Oz in aid of Mary Stevens Hospice next year.
The Dudley-based performer shot to stardom in 2010, when he finished 6th on the X-Factor in a season which included the likes of Cher Lloyd, Matt Cardle and Rebecca Ferguson.
His high-energy performances cemented him in the hearts of the British public, as he covered classic pop songs on the ITV talent show, including a mash-up of Love Shack and She Bangs.
Since appearing on the X Factor seven years ago, Wagner now performs shows regularly across the country and also runs his own advertising business, creating bespoke video messages.
Wagner will play The Wizard in the show on January 23 and 24 at the Brierley Hill Civic Hall.
Amanda Bowen, deputy head of fundraising and lottery at Mary Stevens Hospice, said: “It's a bit surreal, to be honest.
"It might sound ambitious, but we want this show to be the best pantomime our audience have ever been to and having a star of Wagner's calibre performing our title role can only help us achieve that.
"This is one to bring all of your family and friends along to, and all of the money raised across the two nights will go directly towards supporting local people here at the Hospice.
"We can't tell Wagner how grateful we are to him for offering his time and talents to help support our families.”
Tickets for the show are available on the Hospice website at www.marystevenshospice.co.uk/event/the-wizard-of-oz.