"He's so happy right now... Just in life in general and having those kids, you know, it's an incredible feeling for him," Gerber revealed of his longtime pal.
Gerber and his wife, Cindy Crawford, have been by Clooney's side -- with gifts aplenty -- throughout Amal's pregnancy, and have already paid a visit to London to see the twins since they were born on June 6.
"I did see the babies, Cindy and I went to London and went to the house and spent some time with them," Gerber shared. "The kids are the perfect mix of George and Amal. I mean, they really are so cute!"
Gerber and Crawford, who made special Casamigos onesies for Alexander and Ella, made sure the tequila brand was readily available for Clooney when his wife finally gave birth.
"I guess [it will be] a couple more people coming for the ride, but I don't think it'll have that much effect. We'll continue to do what we do and go to incredible places and spend a lot of time together. My kids [17-year-old Presley and 15-year-old Kaia] will be prefect babysitters for theirs!"
Gerber, Clooney and their Casamigos partner, Mike Meldon, sold the tequila company for $1 billion to alcoholic beverage company Diageo on Wednesday, but Gerber said he doesn't think the decision had much to do with Clooney's new role as a dad.
"When you have kids, it's a feeling that you've never had ever before. So it's not something that you can plan on, but I think that as his kids get a little older and he has that connection as you do with your own kids, it's just natural that you want to be around them all the time," he expressed. "But it has really nothing to do with the brand."
"I think now he can afford to get another nanny for the other kid, and maybe another for himself!" he joked.
"When George and I started it, we really we made Casamigos just for us to drink," Gerber said. "We're gonna stay 100 percent involved in the brand. I think that I'll still definitely be running the company, George will still be involved as he was from day one, and so will Mike, and the rest of our team will stay together. We'll continue to do as we always have, and we'll come up with some more interesting, creative ideas."
See more on the Casamigos deal in the video below.