This is definitely a hoax story.
Adele wouldn't risk her credibility by becoming such a sellout after all she has said about people who put their names to products (I think she even singled out diet coke).
The media would have a field day - they built her up and we all know how they love to tear things down.
I also can't think of any make-up brand which promotes the overly made-up look that Adele favours. That's stage make up. It's all about the natural look now