'Game of Thrones' Season 7 Spoilers: 17 Characters Confirmed; Lyanna Stark Not Jon Snow's True Mother? [VIDEO]

The "Game of Thrones" Season 7 is slated to make a comeback in the summer of 2017. Leaked reports have surfaced online to confirm the presence of the largest casting for the HBO series. Season 7 is also rumored to reveal Snow as a Martell-Targaryen instead of a Stark.

Filming for the "Game of Thrones" Season 7 has already commenced and on-set spoilers have already been spotted online, Watchers on the Wall reported. The HBO series has reportedly been filming a lot in the outdoors in locations that include Spain. However, the report that revealed the leaked images apparently did not reveal any live footage.

Leaked images allegedly confirmed 17 characters for "Games of Throne" Season 7 including Ser Jaime and Queen Cersei Lannister, Qyburn, Ser Bronn of the Blackwater, Ser Gregor Clegane and Queen Daenerys vtyuikjhgyujkjTargaryen. It is also speculated that Targaryen will be spending some time at the Dragonpit in King's Landing.

Other characters included are Ser Gregor Clegane, Ser Jorah Mormont, Missandei, King Euron Greyjoy, Tyrion Lannister, Varys, King Jon Snow, Ser Davos Seaworth, Theon Greyjoy, Podrick Payne and Brienne of Tarth, Sandor Clegane. "Game of Thrones" Season 7 is believed to be a larger cast than the previous installments even more than the Purple Wedding. The previous installments reportedly cast two thirds smaller than this season.

Meanwhile, "Game of Thrones" Season 7 is expected to reveal Jon Snow's true origins. Jon Snow, played by Kit Harington was confirmed to be the biological son of Lyanna Stark played by Aisling Franciosi. In the season finale of Season 6, Rhaegar Targaryen was also believed to be Snow's father, Gizmodo reported.

"Game of Thrones" Season 7 is believed to unveil the mysterious whisper of the dying Lyanna to her brother Ned played by Robert Aramayo. It is speculated that Snow's Targaryen ancestry may have been through the House of Martell. Snow may be in fact the child of Elia Martell and not of Stark. Watch the "Game of Thrones" Season 7 | Filming Update | Weekly Spoiler Report