As shown at the end of episode 65, in Dragon Ball Super episode 66 (scheduled for streaming this Saturday in the US), Goku and Vegeta will wear the Potara Earrings to once again fuse into Vegito. With the power of god ki, Vegito will be able to take his power to new heights as a Super Saiyan Blue warrior.
According to Animedia Magazine via Herms98, Super Saiyan Blue Vegito will be able to use Final Kamehameha. What’s interesting is this technique has never been used in Dragon Ball before – it’s a video game exclusive technique.
On a side note, the magazine mentions Vegito has a weakness not normally in Potara Fusions. It seems like something we will see in, if not the next episode, then in one of the episodes coming soon.
There has been debate about the following technique from Dragon Ball Z being the Final Kamehameha, however, it’s hard to say since Vegito never actually yells anything.
And it looks quite different than what’s shown in the episode 66 preview. We believe Final Kamehameha is being cued up for usage at the 8 second mark.
Final Kamehameha in Dragon Ball Xenoverse 2 by Super Saiyan Vegito looks more similar, to us anyways, to what is shown in the Dragon Ball Super preview. The obvious difference is the color due to god ki, but the stance is what makes them the same technique. At the 50 second mark, you can take a look at Super Saiyan Vegito unleashing the Final Kamehameha.