Members of the studio audience clapped and pointed as Pitt, wearing a blue button-down shirt and a pageboy cap, cheered from his seat, CNN reported. That got DeGeneres' attention as she spotted the star of the upcoming movie, "Ad Astra," sitting near the back of the auditorium, Entertainment Weekly reported.
"Hi, Brad. What are you doing?" DeGeneres asked.
"Don't mind me, just came to see the show," Pitt said. "Great show, by the way, so far. You're killing it."
"Well, do you want to come sit down here," DeGeneres asked.
"No, I'm good," Pitt said. "Thanks, though. Carry on."
After Pitt kept interrupting DeGeneres from the audience, he finally made his way to the stage, taking the seat held by actor Sean Hayes, CNN reported.
It was Pitt's first appearance on DeGeneres' daytime talk show in eight years, Entertainment Weekly reported.
The two chatted about their shared interest in a woman at a party hosted by Melissa Etheridge more than 20 years ago. Pitt said he was "flattered" when DeGeneres hit on his girlfriend, CNN reported.
Pitt and the TV host met at a pool party at Melissa Etheridge's in the late '80s or early '90s, where Pitt says, DeGeneres was hitting on his then-girlfriend.
DeGeneres then noted she dated another one of Pitt's former girlfriends, but the two stars did not go into detail.
'We'll talk about that later," DeGeneres said.
"After the show," Pitt said.