One of the unanswered questions in planet formation is: when and where substellar companions form? We recently detected a substellar brown dwarf companion bound to the protostar BHB 2007-1, this is the first discovery of a companion around a protostar. The companion is responsible for the 70 au cavity of the protoplanetary disk. The system also presents a jet detected in the near infrared. BHB 2007-1 offers a unique laboratory to study planet and star formation, and the interaction between the substellar companion and the circumstellar disk. Further GRAVITY observations will better characterize the brown dwarf companion detected.