Another role Emily embraces is that of older sister and guiding light to Ezra.
The 28-year-old is blowing everyone away on the current season of The Voice, thanks to her powerhouse vocals.
"It's almost like I'm living in a dream," Ezra tells us.
"Knowing that I was brave enough to audition for The Voice, turn a chair, be on that stage, it's all been so surreal!"
Like their tennis-playing namesakes, these Williams sisters make sure they always have each other's back.
"There's never sibling rivalry, who's got time for that?" says Ezra.
"She gives me goosebumps every time she takes to the stage!" adds a proud Emily.
"It's such an exciting time for her!"
Emily has shared some of the wisdom of her experiences with her younger sibling.
"The advice I gave her was to be herself and enjoy the ride. Sometimes it's really easy to get caught up in the process and you forget to enjoy every moment."
With their sister Lavina also a performer and former [Australian] Idol contestant, Emily says you never quite know when a Williams is going to pop up on a stage.
"Having famous sisters is so much fun!" adds Ezra excitedly.
"You get to go backstage, collect VIP lanyards, and meet other celebrities. I'm very lucky."