The 41-year-old actress stars opposite the Sports Illustrated model in 'The Other Woman' - where their alter-egos seek revenge on three-timing lover Mark - and although Kate is famous for being a beautiful model, Cameron insists she is "amazing", "smart" and "wise".
Speaking in Britain's HELLO! magazine, Cameron said: "Kate is the greatest - and what's behind the boobs is unbelievable. It's incredible how smart she is and how wise she is and how wise she is and how she sees everything. She doesn't miss a thing. She calculates everything so fast. She's like a bullet. She just shoots it right back and you are like, 'God bless you, you are amazing.' "
Cameron - who is also joined by Leslie Mann in the big screen comedy - doesn't like competition between women and doesn't believe in jealousy.
She explained: "You know what? I hate competition between women. I'm not a competitive person, I'm always about celebrating people. I want everybody to succeed and definitely, when it comes to other women, I want them to succeed. I don't believe in being jealous of other people for their beauty or their talent or their ability. That's just something I am not really into."
Kate, 21, recently claimed her life would be "so much easier" if she had smaller breasts because she wouldn't always have to wear a support bra.
She said: "I wish I had smaller boobs every day of my life as I would love to wear spaghetti tops braless or go for the smallest bikini designs. Every single day I'm like, 'Oh man, it would be so much easier,' especially if people didn't constantly bring them up."