Speaking out over the video today, Simon backed Tulisa and described the boyfriend who posted the video online a "scumbag."
Simon said: "What she was doing was not illegal. You are allowed to do this stuff in your bedroom, but you don't want the tape to come out."
Supporting Tulisa, the X Factor boss insited: "It makes no difference with me about her coming back on the show — 100 per cent.
"I mean, God, if I said no (to her coming back) it's allowing every sleazebag in the country to wreck somebody's career when she didn't do something wrong.
"The public are very, very a) forgiving, and b) understanding. But I hope they don't forgive the person who did it."
The music mogul also blasted the ex-boyfriend who supposedly leaked the video earlier this week, telling The Sun this morning: "Whoever he is, he's a scumbag — and I'm being really conservative with my words here.
"It's disgusting, repulsive. He's embarrassed her and he's got no right to put her in this position.
"He should literally find a hole and hide in it for the next week. It really, really annoys me. It's like, 'Who do you think you are?'"
And Simon quipped: "I am going to watch it tonight."