Astronomers have discovered a companion star in an incredibly tight orbit around Betelgeuse using the NASA and U.S. National Science Foundation-funded ‘Alopeke instrument on Gemini North, one half of the International Gemini Observatory, partly funded by the NSF and operated by NSF NOIRLab. This discovery answers the longstanding mystery of the star’s varying brightness and provides insight into the physical mechanisms behind other variable red supergiants.