M31 RV is a possible red cataclysmic variable star located in the Andromeda Galaxy (M31) that experienced an outburst in 1988, which was similar to the outburst V838 Monocerotis experienced in 2002. At peak brightness, M31 RV was the most luminous red supergiant in the Local Group. Such objects have been called luminous red novae or intermediate-luminosity red transients. During the outburst, both V838 Mon and M31 RV reached a maximum absolute visual magnitude of -9.8.