Reported in The Astronomical Journal [doi.org] (full article is paywalled), KELT-4Ab [wikipedia.org] orbits one of the stars in a triple stellar system. Considered a "hot Jupiter" [wikipedia.org] because of its large size and small orbit, it is only the fourth planet that has been found in association with a triple star system. KELT-4A is the brightest star in the system. KELT-4B and KELT-4C, separated from each other by about 10 astronomical units (AU), form a binary, about 328 AU distant from KELT-4A. The system is about 685 light-years from us.
The planet was detected in a survey by the Kilodegree Extremely Little Telescope [wikipedia.org]. Scientific American [scientificamerican.com] has a story about the discovery.