The comedy star will act as quiz master in Rhod Gilbert’s All You Can Eat Panel Show Buffet and he will be joined by guests from the world of comedy, music and sport.
The performances will take place at Aberdare Coliseum on June 30 and July 1 and at the Park and Dare Theatre in Treorchy on July 2.
The shows are part of Gilbert's fundraising efforts for Velindre’s Patagonia Trek. After conquering Mount Kilimanjaro for the charity in 2013, he will be leading a 50-strong group on a gruelling trek in November as they celebrate the 150th settlers arriving in South America.
Rhod Gilbert just metres from Kilimanjaro's summit during his previous challenge for Velindre
He said: “In 2013 I bought a pair of walking boots to climb Kilimanjaro for Velindre Cancer Care, and I want to get the full use out of them, so I'm taking on Patagonia this year.
"I'll be joining other trekkers in the 150th anniversary celebrations of the first Welsh settlers there, and hopefully raising a shedload of cash for the charity. Spending a lot of time in Wales, I hear so many people speak so highly of Velindre.
"It seems almost everyone is touched by cancer at some point, and Velindre's name comes up time and again, the amazing quality of its care and its staff's incredible capacity to afford people dealing with cancer great dignity. I cannot think of a better cause.”
Andrew Morris, Head of Fundraising at Velindre, said: “We are incredibly grateful to Rhod for his support, and these three nights should be absolutely fantastic – the show 18 months ago sold out in less than two hours, and given Rhod’s popularity I think it will be a similar story this time around too.
"There will be lots of surprises and special guests and it will be a great night, raising vital funds for Velindre."