Why did Leonardo DiCaprio make that face at the Globes?

Leonardo DiCaprio holds his award for Best Actor, Motion Picture, Drama, for "The Revenant", at the 73rd Golden Globe Awards in Beverly Hills, January 10, 2016.

Paul Drinkwater/NBC Universal/Reuters

Leonardo DiCaprio became a trending topic during Sunday night's Golden Globes for one particular moment -- and no, we're not talking about his win for "The Revenant."

The 41-year-old actor made quite a face when Lady Gaga, who was walking toward the stage to accept her award for Best Actress in a Limited Series or TV Movie, touched his back as she walked by. Caught off guard, DiCaprio noticeably jumped in his seat and winced. The moment exploded on social media with numerous GIFs, Vines and screenshots.

"Oh lord -- that's trending, huh?" DiCaprio said when ET's Cameron Mathisonbroke the news in our backstage interview room that that memorable moment was the talk of the Internet.

DiCaprio had a completely logical explanation for why he made the face he did when Lady Gaga brushed by him.

"I just didn't know what was passing me -- that's all!" the "Revenant" star admitted.

DiCaprio won a Globe himself for his harrowing performance in the gritty film.

"This is a type of film that you won't see coming out of the Hollywood studio system very often," he said. "It's an epic art film and I'm just so happy it got recognized tonight."

"The Revenant," which co-stars Tom Hardy, took home three awards, including Best Director for Alejandro G. Inarritu and Best Motion Picture, Drama.

"I want to make more movies like this, and I want the studios to take more chances on movies like this," DiCaprio added.

Meanwhile, DiCaprio brought his father, George, as his plus-one to the glitzy, star-studded awards show.

"I'm happy to bring my dad," DiCaprio told ET's Nancy O'Dell on the red carpet. "I don't think he ever gets to go on stuff like this, so it's gonna be a fun night for us."

But seriously, let's relive the DiCaprio-Gaga moment one more time ...

To find out more about DiCaprio's father, press play on the video below to watch the newly-minted Globe winner's ET interview!