The historical record is sketchy on detail concerning Ankhkeperure Smenkhkare. Some think that this was anther name for Nefertiti. The various chronology suggestions allow for Smenkhkare to be either Tutankhamun's father or brother.
One piece of evidence for the existence of Smenkhkare as a discrete male ruler is the carving shown above. The figure on the left looks like Akhenaten, but the one on the right has different facial features, while both have the royal ureas on their brow.
A box from the tomb of Tutankhamun includes the text "King of Upper and Lower Egypt, Lord of the Two Lands, Ankhkheperure Beloved of Neferkheperure (Akhenaten)" Alongside this are written the name of Akhenaten, and "King's Chief Wife Meritaten".
Whoever this king was, they had a reign of at least 3 years, there is an inscription which says "Year 3, third month of Inundation, day 10. The King of Upper and Lower Egypt, Lord of the Two Lands Ankhkheperure Beloved of Aten."