  Beta Cen is a bright Beta Cephei variable and has long been suspected to be a
binary. Here we report interferometric observations with the 3.9-m
Anglo-Australian Telescope at a single epoch which show the star to be a binary
with components separated by 15 milliarcsec and having approximately equal
luminosities at 486 nm. We also present high-resolution spectra taken over five
nights with the ESO CAT which show Beta Cen to be a double-lined spectroscopic
binary. We identify two pulsation frequencies in the primary. Further
spectroscopic and interferometric studies of this double star should allow
determination of its orbital parameters and component masses.
