It sounds crazy, but thanks to the miracles of machine learning, this is actually possible now. You can find the program here:
https://www.reddit.com/r/deepfakes/comments/7ox5vn/fakeapp_a_desktop_tool_for_creating_deepfakes/

I could see some amazing (and potentially terrifying) possibilities for this.

You can see examples of the effect that it can produce here:
https://www.reddit.com/r/deepfakes/

Oh, shit, yeah, I meant to post this article in off-topic today:

https://motherboard.vice.com/en_us/article/bjye8a/reddit-fake-porn-app-daisy-ridley

All together now, folks: REALISTIC BEA ARTHUR PORN WITHIN OUR LIFETIMES!!!

What a world, gang, what a world.

I HONESTLY do not understand the need to put some celebrity's face onto a pornstar's body. Pretty sure if you can CGI-in a celebrity's face, you can just as easily MAKE UP a pretty face.

Jesus God, that's creepy. No, thanks. I'll just stick with the faces of women who actually sign up for WAM.

Came across* this the other day (disambiguation - noticed*)

Bea Arthur in the US Marine Corp.

1943

"Come on y'all get fappy... "

Do you think celebrities attach porn stars' faces to THEIR bodies?

Way too young.

If anyone out there can make some Barbara Stanwyck wam...

How did Granny never fall into a mud puddle on THE BEVERLY HILLBILLIES?! Let's fix that.

Yes!

"Iss ther anny viddeo ov this? Cant fin on youtub"