8 Dec 2006: ULTRACAM observations confirm for the first time the existence of brown dwarf donor stars in cataclysmic variables. While the existence of such sub-stellar donors has been predicted by theoreticians for many years, their faintness impeded so far an unambiguous detection. ULTRACAM on the William Herschel Telescope has been used to observe SDSS1035+0551, a faint CV that the Warwick team found to be eclipsing in an early study with the ESO Very Large Telescope. A model to the high time resolution light curve delivered by ULTRACAM allows an accurate measure of the donor star mass of 0.052 ± 0.002 solar masses, which is well below the limit for central hydrogen burning. This research has been published today in Science and the unedited manuscript is available on ArXiV.