The one-off special follows the pair as they navigate the Welsh wilderness together, including Snowdon, and camp out every night together in a basic tent.
A source told The Sun: "Getting these two together is a no-brainer for ITV bosses, though the random challenge might leave a few viewers scratching their heads as neither have huge experience of surviving outdoors.
"Fortunately Freddie does have some experience of working closely with a comedian as he's used to filming with Paddy McGuinness on Top Gear.
"Though he won't have worked quite as closely as this before, as they will be sleeping centimetres away from each other on their jaunt in Wales."
The programme has already been filmed and will air on ITV later this year. body check tags ::