The Gossip singer admits she and the 36-year-old supermodel are close, but she insists on using her full name when they are together as she is still in awe of the British beauty.
She told Britain's Marie Claire magazine: "Oh my God, I still can't call her by her first name, I'm like, 'Oh Kate Moss, I can't go in there!'
"We're not super good friends, not because we don't like each other. We're in two different circles."
However, she claims her relationship with the British-born beauty is genuine, as her looks are just one part of her career.
She said: "I do think she's helped me a lot by being a really cool bad-a*s person. She likes what she likes and she likes who she likes and she just happens to be really gorgeous and good at what she does."
Beth also believes Kate is the reason she has her plus-size clothing range with UK retailer Evans, which is part of Sir Philip Green's Arcadia group, the parent company of Topshop.
She revealed: "She is the reason I have the line at Evans. Because she had her line at Topshop and she was trying to get Philip Green involved. And when I told her about Evans she was like, 'Finally, two years later!' "