  UN J1025-0040 is a quasar at z = 0.6344 that shows an extremely bright post
starburst population of age ~ 400 Myr (Brotherton et al. 1999). Images of UN
J1025-0040 show a nearly stellar object 4.2 arcseconds SSW of the quasar. We
present imaging and spectroscopy that confirm that this object is a companion
galaxy at redshift z = 0.6341. We estimate an age of ~ 800 Myr for the dominant
stellar population in the companion. The companion appears to be interacting
with the quasar host galaxy, and this interaction may have triggered both the
starburst and the quasar activity in UN J1025-0040.
