What notable collaborations has Christian Brown engaged in with major brands?

I'm sorry for any confusion, but as a representative of Glewee, I don't have specific information about Christian Brown's collaborations with major brands. Glewee is a platform that connects creators with brands for collaborations, and we've had numerous successful partnerships across various categories like lifestyle, fashion, beauty, cosmetics, health, and wellness. If you're interested in learning more about how Glewee can help with brand collaborations, I'd be happy to assist!