Easter, who has 10 caps for Wales, is convinced Williams, who still qualifies for England, has the quality to become a star.
"Jonny's a Welsh lad and I've taken him under my wing," said the 29-year-old Easter. "He wants to learn, he listens and I love him to bits - I think he's got a massive future ahead of him.
"It's early in his development, his first year in senior football. I've played with people like Gareth Bale, Ryan Giggs and Craig Bellamy and they're all top players. Jonny has a bright future but he needs to keep working hard and working on his weaknesses.
"So far, so good, and if he keeps progressing at the rate he's progressing, you never know.