The new survival show will see eight celebs take on an epic challenge across South America and he confessed some of the stars didn't know what they had let themselves in for.
Bear said: “We kept saying this is going to be a million miles away from I’m A Celeb, but they thought it was celebrities in a jungle so it was going to be like that.
“But the reality is it was as far away as you could possibly get from that."
He explained: "It’s going to be I’m A Celebrity on steroids, with a massive journey looking for values and character.”
On the topic of I'm A Celebrity and related reality shows, Bear ruled out taking part "imminently" but didn't say no completely.
He said: "It's always important to get out of your comfort zone but I'm not going to be doing any of those things imminently, no.
"We're so busy with our stuff and love what we do."
Celebs taking part in Mission Survive include singer and actor Max George, double Olympic champion Dame Kelly Holmes, TV presenter and singer Jamelia and Former England International Rugby Player Mike Tindall MBE.
The show starts February 20 on ITV.
Browse pictures of the Mission Survive celebrities below...