Fletcher has acted as director and coach since Collyer arrived in 2022 from Brighton.
Collyer told manutd.com of the former United midfielder's influence: “I signed and I remember I saw Darren Fletcher.
“He came and spoke to me, which was obviously a big thing, because he’s a player who I’d say I play like.
“So to see him come and speak to me gave me great confidence and the belief that I could achieve things at this club.
“I think it’s important to know things about the club.
“With Fletch, I think, with my game, it’s quite similar to his and I think that’s why it’s great for him to be around, from my perspective.
“I can learn from him, always speak to him and get his opinion on things.”
Recalling his debut against Fulham, Collyer also said: “I remember Fletch rang me and said ‘you’ve made the squad, congrats’.
“I just remember being really happy – I called my dad and mum and shared that with them. I was buzzing and it was a great experience going to the stadium, being in the changing room.
“My first proper experience being around it, for a big game, and yeah, I think with experience like that, you can keep building on it and you’re only going to get better.”