WILL + GRACE star Debra Messing called on the hypnotist who helped her quit smoking when faced with having to play an "aquatic showgirl" - because she's terrified of being underwater.

The actress plays a Las Vegas, Nevada mermaid in Drew Barrymore's new film LUCKY YOU and was terrified when she found out there was no stunt double for the underwater scenes.

So she headed back to the hypnotist who cured her of her smoking habit five years ago, and asked him to give her a quick fix, so she could cope with 16 hours of aquatic work without freaking out.

She says, "I had a full mermaid costume... They put me in a tank with 2,000 fish and I had to lip-sync and dance underwater with sharks and stingray.

"It was the most traumatic thing I have ever experienced in my entire life but I'm proud I got through it.

"When they offered me the part, they said, 'We just wannna make sure that you don't have a phobia of water or fish... because you're not gonna have a stunt double,' and I was like, 'Oh c**p,' because that's one of my phobias.

"I did not mention this and then I went to a hypnotist and the hypnotist got me through it... He just talked me through it."

But the hypnosis was only temporary and Messing insists she'll never repeat the experience: "I will never set foot in a tank again. It was 16 hours I was underwater - as a mermaid."