Ben Affleck Says Catch With Tom Brady Almost Better Than Kids' Births

Ben Affleck has done a lot of cool things over his 52 years walking the planet ... but says the opportunity to run routes for Tom Brady was one of the greatest days of his life!!

The "Accountant 2" star chopped it up with Jason and Travis Kelce on the latest episode of "New Heights" ... and at one point in the convo, the brothers asked all about his one-on-one training sesh with the GOAT when they were vacationing at the same spot.

"To this day, aside from the birth of my children, that was the greatest day of my life," he said.

Affleck admitted he's unsure how helpful he was to the seven-time Super Bowl winner ... but his play-by-play of the whole thing was entertaining nonetheless.

"Alright, run as fast as I can, turn around," he said. "I fix to look at him, he's been waiting 45 minutes. I caught it because I was afraid of breaking my nose more than anything else. And then after a few of those, he's like, 'Alright. We'll put some air on it.'"

He then recalls the final play they ran ... with Brady pretending it was fourth down with 23 seconds to go in the Super Bowl. Affleck claims all Brady told him to do was "run."

"I'm like wondering when's this ball going to show up," he said. "And I look, I just feel like right out in front of me. And it was a little far for me. I think he probably adjusted back, and I reach out and I have to go all out extend, I f***ing catch it."

The story got TK and JK hyped ... cheering as Affleck wrapped up the story. Ben joked it felt so real that he thought he had actually won a championship.

"It was the nicest thing anyone has ever done for me," Affleck said.