It's Emir Ksasan, Willie Weeks never wore a 'fro, even in the mid-seventies!
That is also the (Mike) 'garson band' backing Bowie in that vid - with inter alia David Sanborn (sax), Dennis Davis (dr), Carlos Alomar (guit), Earl Slick (guit), Pablo Rosario (perc) and Emir Ksasan on bass plus of course Mike Garson as musical director/keyboarder. There is a picture on twitter of the garson band (which when not backing Bowie gigged low-key with Luther Vandross singing)
and it pictures Ksasan in the middle with the bass planted to his feet, the Gibson neck and headstock visible.
(left to right: Alomar, Davis, Garson, Ksasan, Rosario, Sanborn, Slick).
Unless I'm gravely mistaken, Bowie never had a white bassist touring with him again after he ditched Trevor Bolder. Herbie Flowers, Mark Plati, Tony Visconti and Tim Lefebvre (all of them white) played on some albums, but on tours it was Willie Weeks, Emire Ksasan, George Murray, Carmine Rojas and Gail Ann Dorsey, all of them black (wo)men (ok, Carmine probably only had a touch of black DNA in him). Tin Machine with Tony Sales was the only exception to the rule.