Len confirmed last year he was quitting Strictly and the 2016 series would be his last.
After more than a decade behind the judges' desk, he was replaced by Shirley Ballas on the BBC One series this year.
He returned to the BBC this week to chat on Breakfast, and spoke of his admiration for Shirley.
Len said he was glad to see Shirley using technical terms, explaining: "I started off full of double reverse spins and all that but then I was told, 'Well, no-one knows what you're talking about'.
"They're back in, good for them."
On Shirley, Len continued: "I think she's done great. I really do. She's her own self, she's got good critiques."
And he also defended the new judge after she received criticism over some of this year's dance off decisions.
"I remember I got terrible stick once. With the dance-off you have to just judge that dance," he added.
Meanwhile, Len suggested that this year's final was anyone's to win.
Gemma Atkinson, Joe McFadden, Debbie McGee and Alexandra Burke are the four remaining celebrity contestants.
Len said: "What's great on Strictly is when you get a final and you really don't know who's going to win it".
And he added: "What's great, with the viewers, they appreciate those that have never danced before."
Strictly Come Dancing 2017 airs Saturday night from 6:30PM on BBC One.