We report a bicontinuous cubic phase forming in the presence of the Influenza HA fusion peptide in coarse grained molecular dynamics simulations. Starting from a random mixture of DOPE, water, and fusion peptides, we observe spontaneous formation of a stable bicontinuous phase. Unlike all previously reported bicontinuous cubic phases the one formed in our simulations is a single phase in the sense that there are no multiple isolated compartments of water or lipid.