We report the discovery by B.G. Harris and S. Dvorak on JD 2455224.9385 (2010 January 28.4385 UT) of the predicted eruption of the recurrent nova U Scorpii (U Sco). We also report 815 magnitudes (and 16 useful limits) on the pre-eruption light curve in the UBVRI and Sloan r' and i' bands from 2000.4 up to 9hr before the peak of the 2010 January eruption.