Jack White collaborated with Pearl Jam during a performance that took place at Portugal's NOS Alive Festival on Saturday.

They covered Neil Young's classic song "Rockin' In The Free World." While singing "Porch," Pearl Jam seemingly paid tribute to White. The latter performed at NOS Alive prior to the band's appearance. After Pearl Jam sang its hit song, "Alive," White joined them on stage to close the band's set. White had multiple solos throughout their cover of "Rockin' In The Free World."

White's surprise appearance at Pearl Jam's concert was not the first time that they worked together. In 2016, Pearl Jam played a secret Third Man Nashville gig in Nashville where White was also featured. At that time, they sang "Of the Earth."

Pearl Jam Summer Tour

In related news, Pearl Jam will perform at London's O2 Arena on July 17 before the members return to Seattle for their series of stadium tours. Pearl Jam will play at the Washington-Grizzly Stadium in Missoula on Aug. 13. On Aug. 18 and 20, the band members will head to Chicago for their series of performances.

Pearl Jam will close its short summer tour with a two-night show at Fenway Park in Boston on Sept. 2 and 4. Earlier this year, the band also announced its "Home Shows" in Seattle's Safeco Field on Aug. 8 and 10. The proceeds from the concert of up to $1 million will be donated to fight homelessness in Seattle.

In the next year, the band also hopes to raise at least $10 million to further alleviate the problem. Pearl Jam will be seeking the help of local businesses, non-profit organizations, and government agencies to assist them in pushing for their plight.

Jack White's Bat Inducted

Meanwhile, White also made headlines recently after his bat was inducted into the Baseball Hall of Fame. White used the bat during a charity baseball game outside Cooperstown, New York on May 27. The sports gear was designed by the singer's baseball bat company Warstic.

Following the baseball game, Warstic created 50 limited-edition replicas of White's bat that the singer also signed individually. The bats were auctioned for charity, and the proceeds went to Well For Culture.

White gained interest in baseball after he received a tour of the Baseball Hall of Fame in 2014. Prior to this, he was already a huge fan of the Detroit Tigers and Mr. Tiger Al Kaline.