We report on the discovery of an apparent triple radio structure hidden inside the radio bubble of the ultraluminous X-ray source Holmberg II X-1 . The morphology is consistent with a collimated jet structure , which is observed to emit optically thin synchrotron radiation . The central component has a steep radio spectrum and is brighter than the outer components indicating a renewed radio activity . We estimate a minimum time-averaged jet power of \sim 2 \times 10 ^ { 39 } erg s ^ { -1 } that is associated with a time-averaged isotropic X-ray luminosity of at least 4 \times 10 ^ { 39 } erg s ^ { -1 } . Our results suggest that Holmberg II X-1 is powered by a black hole of M _ { BH } \geq 25 M _ { \odot } , that is inferred to be accreting at a high Eddington rate with intermittent radio activity .