The ex-Scotland striker spent two spells on Merseyside, firstly between 1994 and 1998, and after a stint at Newcastle returned from 2000 to 2006.
The Stirling born man made 239 appearances for the Goodison Park club, and his countryman Moyes has confirmed he is now back.
“Duncan came about a month ago and met me. He wants to observe us and see what’s going on. He is back and helping Alan Irvine,” Moyes told the club’s official website.
“He is not a qualified coach yet, because he is going through his badges, but we have got him in and he’s happy to do the time and he’s working down at the academy.
“He is showing he really wants to do it. He is putting the hours and the effort in. He still has to get his B licence and A licence, but he will get the chance to take some sessions.
“It could lead to something here, but what you need is your qualifications, that is the first thing.
“I have to say I didn’t forsee him going into coaching when I had him as a player. But Duncan has been away for five years and he has come back – I think he misses the smell of football a wee bit,” Moyes concluded.
By Gareth McKnight