It's pretty clear that Bette Midler is not a fan of Lady Gaga ... especially after Gaga rolled on stage as a mermaid in a wheelchair during a concert in Australia. Ms. Midler claims the eccentric singer ripped off her act.

Bette Tweeted the following:

    "I’m not sure @ladygaga knows that I’ve performed my mermaid in a wheelchair for millions of people -- and many of them are still alive....."

    "Dear @ladygaga Ive been doing singing mermaid in a wheelchair since 1980-You can keep the meat dress and the firecracker t**s-mermaid's mine."

Watch Gaga's wheelchair performance in the video below. Check out Bette's old school antics ... after the jump.