Brand, 37, was linked to the Ghost star, 50, last month, but he is adamant there is no romance between them.
He tells The Sun newspaper: "Demi Moore, as far as anything more physical goes - she's just at yoga. I really like her, she's really lovely. I just see her at yoga. She's an older lady, she's incredibly beautiful but that's that."
The British comedian admits he is a big fan of yoga, and even invited his classmates into his house in Los Angeles for a group session.
He adds: "It's full of amazing women. That's a fact. They are all filled with sexual energy. It has been brilliant.
"The yoga centre I had been going to sacked our instructor, so I have moved everyone into my house. I had 30 people doing it in my house.
"I had all the crew on my TV show doing yoga in the studio the other day too. There were 100 people doing it. It's not your normal yoga. It's like proper chanting, full-on stuff - not for the faint-hearted. I like the yoga thing, it's the dawning of a wonderful new era. It's proving to be an interesting new phase for me - yoga, transcendental consciousness, meditation, good-looking people. It's the dawning of a new Sixties."