Watch Robert Plant, Chrissie Hynde Perform Together in London

Singers duet on "Bluebirds Over the Mountain" and Pretenders' "2000 Miles" at Royal Albert Hall

Chrissie Hynde made a surprise appearance during Robert Plant and the Sensational Space Shifters' concert Friday at London's Royal Albert Hall.

Chrissie Hynde made a surprise appearance during Robert Plant and the Sensational Space Shifters' concert Friday at London's Royal Albert Hall, where the singers performed "Bluebirds Over the Mountain" and the Pretenders' "2000 Miles" together, Led Zeppelin News reports.

Plant's rendition of Ersel Hickey's "Bluebirds Over the Mountain" appears on the Led Zeppelin singer's latest LP Carry Home; Hynde also features on that album version of the track. The Royal Albert Hall show marked the first time the Rock Hall inductees had played the track live together.

"On a wing and a prayer, we have a beautiful song for you that only Chrissie can sing right," Plant told the audience prior to the Learning to Crawl cut "2000 Miles," with Plant and the Sensational Shape Shifters providing backup as Hynde took lead.

Plant is in the midst of a trek in support of Carry Fire that the singer anticipates will take him through 2018, as he told Rolling Stone in September.

"Anyone who gets tangled up in music and performance wants to keep it going," Plant said. "But by which means do you do it? Cramming the stuff into the suitcase again and playing live? Or is it creativity, another adventure, and trying to impress people who often want to hear how it was rather than how it is? That's what I've been trying to do."