The detection in 1919 of starlight that had been deflected by the Sun was one of the first convincing proofs of Einstein’s general theory of relativity. Now, Kailash Sahu of the Space Telescope Science Institute in Baltimore and colleagues have used the Hubble Space Telescope to measure the analogous bending of light around the white-dwarf Stein 2051B, allowing them to calculate its mass to be 0.675±0.051 solar masses. In addition to the first measurement of the deflection of starlight by a star other than the Sun, the work provides valuable verification of the relation between the mass of a white dwarf and its radius.