Since sex is a natural experience, movie producers and directors often sthrive to include “raw” sex scenes in films to showcase a heightened sense of realism.

While most are fake hanky-panky between actors, others have been verified to be real. In other words, there are mainstream actors and actresses who were supposed to fake it, but ended up doing it for some reason.

Without further ado, here are 10 cases of movie stars who actually did it on the big screen.

Chloë Sevigny and Vincent Gallo

Chloë Sevigny and Vincent Gallo Sex Scene

In the 2003 movie, The Brown Bunny, Chloë Sevigny performed unsimulated oral sex on her co-star and former boyfriend, Vincent Gallo. She fully admitted it and said that there was no reason to wonder about her.

Kieran O’Brien and Margo Stilley

Kieran O'Brien and Margo Stilley sex scene in "9 Songs"

While we expect sex on screen to serve a more abstract function—as a revealing mirror of human nature—some agenda beyond the visible flesh is what people saw in the 2004 film, 9 Songs. While O’Brien and Margo came clean about their real deeds on the set, we still don’t really understand why.

Halle Berry and Billy Bob Thornton

Halle Berry and Billy Bob Thornton Sex Scene in Monster's Ball

In Monster’s Ball, Halle Berry and Billy Bob Thornton literally went overboard and directors had to yell “cut” severally to interrupt their intense lovemaking. The acting was so real that it brought Halle Berry an Oscar for the Best Actress.

Kim Basinger and Alec Baldwin

Kim Basinger and Alec Baldwin sex scene

Reportedly, the two actors filmed all the love scenes in the Gateway in a closed empty room. It’s not hard to understand why Kim and Alec’s sex scenes were so good, particularly if you can remember that the two stars were married while the movie entered preproduction.

Eric Balfour and Lauren Lee Smith

Eric Balfour and Lauren Lee Smith sex scene

After audiences commented that the sex scenes in the 2005 film, Lie with Me, looked totally real, the set revealed that they in fact were. Lauren herself admitted that it was controversial but people would understand that she was trying to portray a strange woman who wasn’t comfortable with the emotional side of relationship, but so great with the physical.

Robert Pattinson

Robert Pattinson

In the 2008 film, Little Ashes, Robert had a very real orgasm in a scene that reportedly called for the star to have an orgasm. The actor admitted to having actually handled the real business below the camera because faking it couldn’t just cut it.

Kerry Fox and Mark Rylance

Kerry Fox and Mark Rylance sex scene

In Intimacy, a 2001 film based on a novel of the same name, the intimacy that Fox and Mark showed on the screen was as real as the oral sex performed by the two stars.

Anna Paquin and Stephen Moyer

Anna Paquin and Stephen Moyer sex scene

If you remember all those hot sex scenes from True Blood, you’ll definitely agree that the two stars went beyond the script right in front of the cameras. Interestingly, Anna admitted to having been intimate with other members of the cast and to have felt entirely comfortable walking around the set naked.

Karl Glusman and Aomi Muyock

Karl Glusman and Aomi Muyock in "love"

Gaspar Noé’s 2015 film, Love, is another controversial film that featured real sex scene between Karl Glusman and Aomi Muyock. Most of the film was not choreographed and the director admitted that he wanted to make his audience feel well “excited”.

Angelina Jolie and Antonio Banderas

Angelina Jolie and Antonio Banderas sex scene

The 2001 Original Sin film has been criticized to have contained real sex between Angelina Jolie and Antonio Banderas’ characters. Jolie and Banderas’ chemistry in the scene seems too real to have been simulated. In previous interviews, the film’s director, Michael Cristofer, also admitted that the scene was in fact real.

This list certainly doesn’t include all A-listers who did it on screen—there are plenty more. And there are several mysterious reasons behind the acts though to be fair to our stars, we’ll just assume that they intended to get perfect performances.