ET sat down with Gerber and Crawford in May, where they revealed that their striking resemblance isn't the only way they're alike.
"It's not even just the way that we look alike," 15-year-old Kaia said. "We have the same mannerisms... just like, the way we react to certain situations is the same -- and I think that's where it really shines through how much alike we are."
"I think the best thing that I tried to pass on to [Kaia] is to just be true to yourself and to feel like you're good enough just the way you are," Crawford explained. "And then, anything else that you want to do, just listen to that voice inside."
See more in the video below.