At the ceremony, director Christopher Nolan praised Zimmer's musical skills.
"To me, there is no composer working who has done more to define the sound of contemporary films," Nolan said.
But when Zimmer took the stage, he quickly turned the attention to Chasen.
"I would like to dedicate this star in loving memory to my mother and friend, the great Ronni Chasen," Zimmer said.
Zimmer said Chasen helped him advance his career in Hollywood. The publicist's killing last month shocked the entertainment community, but hit Zimmer especially hard.
"There's somebody I've been talking to on a daily basis for the last 20 odd years of my life," Zimmer said. "She was the first person at the hospital when my kids were born. There wasn't a Thanksgiving or children's party without her. I feel an acute sense of loss in my heart."
In fact, Zimmer says Chasen is the one who convinced him to accept the star on the Walk of Fame.