The Friends with Kids actress has spoken of removing the tattoo on her forearm in recent months, stating that the artwork had "negative energy".
Speaking on The Ellen DeGeneres Show, she revealed that she has had one removal session, and that it is "incredibly painful".
Host Ellen DeGeneres asked: "You are having a tattoo removed. It's more painful than getting a tattoo from what I've heard."
"I've only done one session on it, but it is incredibly, incredibly painful," Fox replied. "Wherever the ink is, the laser hits it and it sort of pops up like little pieces of popcorn and explodes your skin.
"It's really awful. So kids, don't ever get tattoos. They're not worth it."
Megan Fox recently praised her Transformers replacement Rosie Huntington-Whiteley.
> Megan Fox: 'I'm over Marilyn Monroe tattoo'
The Ellen DeGeneres Show airs in the UK on Really (Sky 248, Virgin 267, Freeview 20) weekdays at 4pm.
Watch Megan Fox talk to Ellen DeGeneres below: