The Flaming Lips know how to throw a party, and the band certainly kept things festive during their SXSW performance Friday night in Austin. After teasing fans with the possibility of a surprise appearance from Justin Timberlake, a man with a green cloth mask wrapped around his head strolled onstage to perform 'Do You Realize??.' But the mystery guest turned out to be not JT, but My Morning Jacket's Jim James.

"Someone told me Justin Timberlake is backstage getting high," Lips frontman Wayne Coyne joked to the crowd. "Do you want me to bring him out?" Following audience chants for "JT" and "Justin!," the shrouded James sauntered onstage to help sing 'Do You Realize??' But despite hints at the presence of a pop superstar, when James' true identity was revealed, the crowd was not disappointed.

The Lips also rocked a new song during their set, turning in 'Always There ... In Our Hearts,' the final track off their forthcoming 'The Terror' album coming out on April 2. Watch (very distant footage of) the Jim James duet above and the new song below.

Watch the Flaming Lips Perform 'Always There ... In Our Hearts' At SXSW

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