Jacob Elordi took over the reins at 'SNL' Saturday night, and his monologue predictably began with THAT "Saltburn" sex scene.

SPOILER -- Jacob's character, Felix, dies and Barry Keoghan's character has sex on his grave.

Jacob got straight to the point ... "If you saw the movie, thank you. If you saw the movie with your parents, I'm sorry. If you saw the movie with your girlfriend, you're welcome."

The Aussie actor, who kicked off the first "SNL" of the year, took questions from the audience/cast, including one where he was asked about that "gross" scene in his movie. Poor Jacob thought it was about "Saltburn," but she was actually referring to "The Kissing Booth."

No sign of Olivia Jade during the show ... but she was spotted at an afterparty ... the two've been dating since the end of 2021. She was there during rehearsals.

Jacob's on quite the run ... aside from "Saltburn" and "Kissing Booth," he starred in "Priscilla" last year. He also stars in "He Went That Way," which was released earlier this month.