Fletcher moved to West Ham on a free transfer earlier this week after leaving Manchester United at the end of the 2015-16 season.
West Ham co-chairman Gold has backed Fletcher to succeed at the Olympic Stadium.
“We went for a coffee inside our state-of-the art Club Store and I bumped into our new signing Ashley Fletcher who was also at the new Stadium,” Gold wrote on West Ham’s official website.
“We had a good discussion and even though you see him as a young man, he is strong and athletic and is a very intelligent individual. I will be very surprised if he doesn't make an impact at West Ham United.”
Fletcher is rated highly and is considered as one of the more promising young strikers in England.
The youngster has yet to prove himself at the top level, but he is certainly talented and can go a long way.
West Ham manager Slaven Bilic has a good record of working with young players, and the 20-year-old striker will learn a lot from him.
It will not be easy for Fletcher to establish himself in the Hammers’ starting lineup, though, and he will have to work extremely hard in pre-season.