The So You Think You Can Dance star, 60, said that he picked Arlene Phillips to join him on the BBC One show because she is "wiser and older" than the performers.
"I wanted someone with the same experience that I've got," he told DS. "I believe in the judiciary being older and wiser than the people dancing. When I was doing the Young Generation, Arlene was doing Hot Gossip, we grew up from the same school.
"Arlene branched off into choreography and was hugely successful. I went off into production. Now, weirdly, we have come back around and our paths have crossed again. I was grateful that Arlene was free [to do the show]."
Last year, Phillips was replaced on the Strictly Come Dancing judging panel by popstar Alesha Dixon and ballet icon Darcey Bussell.
> Click here to read our full interview with Nigel Lythgoe and Arlene Phillips