Couples compete for prize in Love Room.
The couple are used to being in the public spotlight after 15 million people watched them star in a pioneering BBC fly-on-the-wall documentary, The Marriage, in 1986.
The show, the creation of Red Dragon FM, has a pounds 5,000 prize at the end of it with people voted out over seven days.
Marc, an environmental health officer, will miss his first Scotland v Wales match in 34 years.
Celebrities, including rap band Goldie Lookin' Chain and the stars of television stunt show Dirty Sanchez, will set tasks for the contestants.
Vickie Davies, of Pentwyn, Cardiff, and Chris Field, from Caerphilly, both 26, will also go in with Aimee Morgan, 19, and David Stanford, 20, both from Newport.