Fellaini followed Moyes from Everton to Old Trafford two seasons ago but Sir Alex Ferguson???s replacement was sacked last April, just 10 months into a six-year contract.
Fellaini grew close to Moyes during their time together at Goodison Park and Old Trafford so the big Belgian was overcome with emotion on the day the Glaswegian was shown the door.
“When he left I was sad,” said Fellaini in So Foot magazine. “We had heard things on the radio and TV (about Moyes leaving). It was after a defeat to Everton.
“I did not know if it was true or not. Then I arrived the next day at the (training ground) canteen, and I saw him in his suit, rather than his tracksuit. I told myself: ‘This is the end.’
“It was weird. After I had eaten, he summoned me to his office and he told me the news. This is football.
“There were tears. This is normal. I am a human being. I worked with him for six years.
“He was not a second father, but almost. He helped me a lot”.
Like Moyes, Fellaini struggled to deal with the step up from Everton to United last season. United spent ??27.5m on Fellaini but he failed to score a goal in his first year at the club.
The 27-year-old has hit back at suggestions that he was to blame for United’s dour season under Moyes, which ended with the club finishing in seventh place.
“During my first season at Manchester, the team was not performing and I was the scapegoat,” Fellaini said. “Everything was Fellaini’s fault.
“If you pay attention to all this (criticism), you sink. It destroyed me on every side.”
Fellaini was expected to leave Old Trafford last summer, but he has excelled at the club after being given a second chance by Moyes’ successor Louis van Gaal.
“I knew it was going to be difficult when he (Van Gaal) arrived because I was the scapegoat last season. So I told myself I had nothing to lose,” Fellaini added.
“I had one chat with him at the start of the season on my return from the World Cup. He told me there were a lot of players in my position and it was up to me to prove myself.
“After a few training sessions, I felt things were going well. He tested me. He put me up against players who could make things difficult for me, little, lively ones.
“Either one-on-one or in groups of four. He observed me in these games and watched the videos, too”.