Lam also thinks there is more to come from Rees-Zammit, who toured with the British and Irish Lions in 2021.
“He’s only just scratching the surface of his ability,” he said.
“If he keeps progressing on this journey, he has everything it takes to become one of the very best players in the world.”
Rees-Zammit said: “I’m incredibly happy to have committed my future to Bristol Bears. This is the perfect club for me and I’m excited to see what we can achieve here.
“The environment here allows me to express myself and play the game the way I love, and that brings out the best in me.
“Running out at Ashton Gate in front of huge crowds and feeling that energy from the fans is special, and it makes me excited about what we can build together in the years ahead.”