The paradigm of lunar crust formation has been widely applied to other terrestrial bodies, but the nature of early crust building on the Moon remains enigmatic. Here we report non-Apollo-like highland clasts from the Chang’e-5 mission and find high-alumina melts enclosed in a noritic anorthosite. Geochemistry and phase equilibria modeling suggest that the melt is compositionally parental to lunar magnesian-suite rocks, and was sourced from a plagioclase-bearing, orthopyroxene-dominated upper mantle ( ~ 4.5 kbar and 1225°C). It was formed as a direct consequence of upper mantle melting at the onset of gravitational instability. We propose a continuous early crust formation on the Moon, started from multiple anorthositic cumulate flotations, to upper mantle melting caused by small-scale, in-situ overturn, and eventually ended up by decompression melting of lower mantle cumulates following large-scale, global overturn.