BOSTON -- It had just hit 1 a.m. ET early Sunday morning at the Paradise Rock Club on Commonwealth Avenue, and if you weren't there, you may not have believed it.

Deep into the final song of the night for the Hot Stove Cool Music benefit concert, Cubs president of baseball operations Theo Epstein decided to jump off the stage and into the crowd. Pearl Jam frontman Eddie Vedder followed.

The concert, which started in Boston in 2000, was a joint effort between the Red Sox and Cubs to benefit the Red Sox Foundation and the Foundation To Be Named Later. It marks one of a handful of events to benefit the charities during a three-game series between the clubs in Boston this weekend.<o:p>

"It's great to see these two teams come together," Vedder said. "It's nice to see everyone getting along for the greater good. I hope everyone follows their lead."

Vedder headlined the concert for the third year in a row and played for two hours, singing familiar tunes including "Elderly Woman Behind the Counter in a Small Town," and also some covers like "Comfortably Numb" by Pink Floyd and "The Kids Are Alright" by The Who.

While Vedder is a huge Cubs fan -- and could be seen in the stands throughout the club's 2016 World Series run -- he donned a Red Sox hat and helmet during parts of the show.

The Boston and Chicago Hot Stove All-Stars each performed sets, which included musicians like Buffalo Tom's Bill Janovitz, Letters to Cleo's Kay Hanley and Belly's Tanya Donelly.

Former Yankees outfielder Bernie Williams, an accomplished guitarist, even performed with the Boston All-Stars. It was something comedian Mike O'Malley, who emceed the event, cracked jokes about the entire time.

Between sets, O'Malley keep the crowd entertained. That included auctioning items like a cowbell signed by Will Ferrell for $2,000 and a guitar signed by Vedder for a whopping $13,000, with all proceeds going to the foundations.

"It's a simple concept: Just take people's enthusiasm about the Red Sox, and now the Red Sox and the Cubs, and try to convert some of that enthusiasm into fundraising for a lot of nonprofits that do some of the most important work in our society," Epstein said. "One thing I can say for certain: Red Sox fans and Cubs fans are very, very generous and community-minded, and this is just a mechanism to direct some of those dollars toward nonprofits that we know do great work."

Red Sox and Cubs players, coaches and front-office officials all took in the concert from the second floor.

With the ceiling so low, Red Sox starter Thomas Pomeranz 's head nearly touched it. His teammate Chris Sale said he banged his head a few times on it.

Even recently-acquired Red Sox utility player Chase d'Arnaud didn't miss the event. He searched through his suitcase to find a "Believe in Music" T-shirt.

"Everyone is here, it is amazing," said Red Sox knuckleballer Steven Wright .

A plethora of fans wore Cubs and Red Sox apparel. Even a few had Cubs jerseys with the last name "Vedder" across the back. The fans stood the entire night, dancing with their hands held high and cheering like they were at a baseball game. With the stage full of musicians who performed during the show, each played a part in performing Neil Young's "Rockin' in the Free World" to finish out the concert.

As the final chord was played and the lights went up, Vedder spoke.

"This has been an amazing night," Vedder said.