Practical joker Ashton Kutcher, star of MTV's "Punk'd" show, said actress-girlfriend Demi Moore is someone on whom he will never pull a prank.

Kutcher told he has assured Moore that she is excluded from his pranks just in case there should be a genuine emergency.

"If something serious were ever to go down, like if something happens to one of the girls and I had to call Demi, I can't have been the boy who cried wolf," Kutcher said.

The "Punk'd" star said he has also stopped staging pranks on several close friends.

"They're all wise to it, and if anything goes down, they're immediately thinking something's up," Kutcher said.