"She somehow claims because she was in that movie with you, she's your best friend," DeGeneres said. "Let's just acknowledge I am the better friend."
That's when the Pretty Little Liars star made a surprise appearance to settle the debate.
"She told me she was gonna be on the show, we talk every morning," said Witherspoon, clad in a brown polkadot dress.
"You talked to her after you talked to me? That's so funny," DeGeneres responded, putting a possessive arm around Oprah, leading the three to form a group hug.
"Why can't we all just be best friends?" Winfrey then interjected, leading Witherspoon to respond, "I mean, we can, but we're going to be better friends."
DeGeneres then opted to settle the dispute with a who-knows-Oprah-best trivia game.
"If I win, the whole audience is getting a prize from Fandango, and if Reese wins, nothing," she said.
After the actress and the comedienne continued to get most of the questions wrong, DeGeneres finally dubbed herself the winner, then gifting the audience with tickets to see A Wrinkle In Time, out March 9.
During the interview, Winfrey, who is typically a homebody, also gushed about having "the most fun" she ever had at DeGeneres' 60th birthday party, adding that she barely recognized The Weeknd and Leonardo DiCaprio.
"I danced, I drank, I talked to people," she said. "I don't know a lot of celebrities. You are the celebrity that I know, and Reese. But now, I met so many at your party. I'm texting them. I got a lot of numbers."
Winfrey also touched on her initial reaction to President Trump’s tweet calling her "very insecure" following her interview about him with 60 Minutes.
"I woke up and I just thought…," she said, raising her hands in the air. "I don’t like giving negativity power, so I just thought, 'What?' What I actually really did was I went back and looked at the tape to see if there was any place that that could be true. Did I feel like it was slanted or biased. I went back and looked at every tape, I called the producers. I was working very hard to do the opposite of what I was hate tweeted about so, it’s okay."
In addition, Winfrey addressed any rumors on running for president and shared advice on how they can make the most impact following the tragic Florida high-school shooting.
Girls' Trip star Tiffany Haddish also appeared on the show and dished on her Hollywood idol -- who else? -- Oprah Winfrey. Naturally, Oprah surprised Haddish, who immediately took to Instagram to share the good news -- three times!
"SO JUST SO YALL KNOW I POSTED IT THREE TIMES BECAUSE I AM THAT DAMN HAPPY!" the star exclaimed. "YES! YES! YES I CRIED AND YES I ASKED HER TO BE MY AUNTIE! SO ALL THANKS BE TO GOD FOR ALWAYS COMING THRU YOU HEAR MY PRAYS AND ANSWER ACCORDINGLY AMEN!"