Wow -- check out the guy warbling backup on this 1965 live clip of Steampacket featuring Brian Auger and the late Long John Baldry .
Yup, that's a pre-stardom Rod "The Mod" Stewart, as he was known back then. Wotta cutie.
Incidentally, Baldry started out as the r&b/blues purist you see above but by 1967 he had turned into a chart-topping MOR balladeer a la Englebert Humperdinck. Essentially, he played out the entire decades long arc of Stewart's career as one of rock's most reprehensible sell-outs in a breathless two years.
I met him briefly in the early 70s, when he did a show at my old school while touring behind an abortive comeback album with sides produced by Stewart and Elton John. A very nice guy and a pretty good blues-rock record, as I recall.
[h/t Brooklyn Girl]