The 20-year-old has been cautiously introduced into the City first-team squad over the past couple of years and is now an established member, while he is now a regular member of the England senior squad, too.
On Wednesday evening Foden started as England defeated Iceland 4-0, with him scoring his first and second international goals in the comfortable victor for the Three Lions.
De Bruyne was at City when Foden made his debut in 2017, allowing him a front row seat to witness the young wonderkid's progression.
The Belgian reckons the sky is the limit for his team-mate.
"He's doing really well, Phil," De Bruyne told ESPN.
"He's been with us for three-four years, he's still a young man but he's playing regularly.
"He's playing really well, he's evolving, so he needs to keep doing that. So, in a couple of years if he goes the right way, he'll become one of the best players in the world if he wants to."
The last time Foden was on England duty, he was reprimanded and sent home after breaching coronavirus protocol with team-mate Mason Greenwood.
England manager Gareth Southgate is happy his player has put the incident behind him and is able to look forward.
"I'm really pleased for him and his family," Southgate said after Iceland win.
"To have the experience he had in September was really tough for a youngster.
"We all make mistakes. It was a difficult situation to be in. You're walking back through the door and looking at everyone's faces and you know the last time you saw them it was complicated.
"It took him a few days I think to settle into the camp and start to smile a bit more and relax a bit more. We know what he's capable of doing.
"He's one of a few that are going to be very exciting over the next few years for England."