Jack White surprised fans by appearing on stage during Pearl Jam’s headlining set at a music festival in Portugal over the weekend.

RELATED: Neil Young Slams ‘Bulls**t’ Farewell Tours, Insists He’ll Retire When He’s Dead

The former White Stripes musician joined the band at that NOS Alive festival in Lisbon to play a solo-filled version of Neil Young’s classic protest song “Rockin’ in the Free World”.

Before White showed up on the stage, Pearl Jam wove the classic riff from his song “Seven Nation Army” into their own song “Porch”.

RELATED: Neil Young Slams Google For Continuing To ‘Rip Off The Artist Community’

According to Rolling Stone, White and Pearl Jam previously rocked out together at a secret gig in Nashville in 2016.