A day after his first series of Doctor Who ended on the BBC, the star joined the electronic duo to close the Other Stage on Sunday, June 27.
The actor introduced the group's version of 'Doctor Who Theme' and proceeded to don light glasses and join in the performance of the Ron Grainer and Delia Derbyshire tune.
"Yes, Glastonbury," Smith said to the crowd. "So, 2010. Orbital, Orbital, you do the theme tune. Cool! Actually, the screen's gone a bit wibbly. Can I have some glasses please? Wibbly-wobbly timey-wimey, there we go, good!
"So Glastonbury, this is the last song of the evening people, if you're lost... let's make this one count! For Orbital, they're back! For Glastonbury, we're back! Let me hear you cheer, let me hear you roar, for Glastonbury!"