Who Is Jennifer Aniston's BFF? Justin Theroux Ends Reese Witherspoon & Ellen DeGeneres' Great Debate

Theroux is clearing up the great best friend debate!

Jennifer Aniston is famous for her Friends, and many stars have been vying for the coveted spot of best pal. Now, Justin Theroux is weighing in on the great BFF debate.

“Well, I’m Jen’s — one of Jen’s — best friends,” the 46-year-old actor said during a recent appearance on The Ellen DeGeneres Show. “I don’t want to get competitive, though.”

The admission came after DeGeneres, 59, recalled the moment recent guest Reese Witherspoon claimed to be Aniston’s right-hand gal.

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“Somehow she thinks she’s Jen’s best friend when I explained to her that I’m Jen’s best friend,” DeGeneres said. “And I just want you to clear it up with the world that I am Jen’s best friend.”

Theroux chimed in: “I get in trouble if I say she’s the best friend, or you’re the best friend.”

DeGeneres wasn’t satisfied, and soon declared, “the honest truth is I’m a better friend.”

WATCH: Why Jennifer Aniston Will Be Back on TV 13 Years After Friends — and the Key Role Reese Witherspoon Will Play

After some disappointing news, The Leftovers star called it a tie.

“I don’t know, she’s pretty good friends with Reese, as well,” he said. “[Aniston] loves you, don’t get me wrong. She adores you … let’s make it equal friends.”

Witherspoon is set to spend a lot more time with Aniston as they work to develop their new television show.

“[I am] so excited,” Witherspoon told reporters at the New York screening of her film Home Again earlier this month. “[We’re having] so much fun brainstorming and laughing and sending each other emails. We’re having a great time.”