After six years at the helm, a poor performance at this summer's European Championship cost the former Manchester City boss his job.
Southgate was overwhelming favourite to replace Pearce from the outset, but only penned a three-year deal to take over as Young Lions boss after speaking with his long-time friend and former international team-mate.
"I have spoken to him three or four times over the last month and I have to say he has been brilliant with me," Southgate said.
"He always said it was a job he loved doing.
"I didn't play with anybody who was more passionate and prepared to give everything for his country than Stuart.
"I know he was extremely proud to do this role as well so it is an awkward situation for me to follow him in that respect.
"But having had discussions with him he felt it was something I should apply for and an experience I would really relish.
"That made it acceptable for me to apply. I would have been a little bit uncomfortable applying for it had we not had that conversation because we know each other so well.
"We played with each other for years in the back four so you do get to know someone pretty well."
Southgate will always be thankful to Pearce for helping him settle into the England team when first called up 18 years ago.
He will, though, never forgive him for taking him to a Sex Pistols concert from which he is "still recovering" - a night out that highlights their differing personalities.
"I think where we are similar is in the pride and passion we have for our country," Southgate said.
"We are completely different personalities and completely different people, but what happens to young players in this country is upper most in both of our minds.
"What happens to ourselves is secondary to that."
It is that focus and drive that has seen Southgate forego his high-profile punditry role with ITV.
"There are two reasons why I have given it up," Southgate, who last year left his role as England's head of elite development, added.
"This is a full-time job and when I was working for the FA previously I was only doing a couple of days a week. It was a two-day job that became a four-day job.
"I didn't want people thinking that if it wasn't going well I had the life raft and in my mind I wanted to be a coach and a manager full-time. I wanted to show I am fully committed to the job."