The collaborative effort of Grammy winners Robert Plant [ tickets ] and Alison Krauss [ tickets ] has enjoyed enthusiastic crowds across the US this summer in support of their release "Raising Sand," prompting the duo to add nine more dates through the fall, including San Francisco's Oct. 3 Hardly Strictly Bluegrass Festival.

Plant, of Led Zeppelin, and Krauss, of Union Station, are dynamic artists in their own right, with distinct vocal signatures and coming from different genres. Yet collectively they produce a rich, unique and soulful sound that has prompted some to suggest that they sound as if they were always destined to make music together.

LiveDaily photographer Tim Mosenfelder attended their June 27 show at the Greek Theatre in Berkeley, CA, and took some photos of the action on stage.