7x17 - Dragon Ball Z: Dragon Box

Having obtained the life of the Elderly Kaioshin, Goku's resurrection is complete! In addition, the elderly Kaioshin gives Goku the Potara earrings that he is wearing. He tells Goku that if two people put on one of each of the two earrings, they will merge together in a powered-up form, much as with Fusion! Goku immediately uses his Instantaneous Movement to relocate to Earth, and gets ready to merge himself together with Gohan.