'Game of Thrones' season 7 release date, plot rumors: Euron and Cersei to form an alliance?

Since 'Game of Thrones' started filming for its seventh season, many fans of the TV adaptation have been keeping their eyes peeled in hope of discovering a few details about the upcoming season before it starts. Recently, a great number of the show's lead cast has been spotted in Belfast, Ireland, which also suggests that a major battle on the seas is underway.
A lucky fan had the chance of meeting a number of the cast in the streets of Belfast while they were roaming the city. Among the stars fans encountered were Lena Headley (Cersei Lannister), Indira Varma (Ellaria Sand), Rosabell Laurenti Sellers (Tyene Sand), Gemma Whelan (Yara Greyjoy), and Alfie Allen (Theon Greyjoy). However, it was Pilou Asbæk's (Euron Greyjoy) appearance which created such a commotion within the fandom.
Euron is the youngest uncle of Theon and Yara. To recap, he killed his brother, the reigning King of the Iron Islands, Balon Greyjoy (Patrick Malahide) in the previous season. Consequently, he attempted to kill his niece and nephew, and he decided to take the throne.
Sources say that Euron might be making an alliance with Cersei next season. In season 6, Euron and his fleet set sail to the Bay of Dragons, formerly known as Slaver's Bay, to offer Daenerys Targaryen (Emilia Clarke) a fleet. However, Theon and Yara beat their uncle to it since they had a head start when they took all of the Iron Islands' ships with them.
Towards the end of the season, the mother of dragons was seen making alliances with many families who were seeking their own vendetta against the Lannisters. To note, Cersei claimed the throne last season and will therefore need to forge alliances to protect herself and her kingdom. Sources say that Euron will battle Daenerys' fleet at sea while they're en route to Westeros.
Recent speculations suggest that Euron possesses the Dragonbinder, the horn that could make the wielder the master of dragons. Will Euron be a mere pawn of Cersei next season? Or will he become a formidable opponent in the forthcoming season?
Fans can catch the seventh season of "Game of Thrones" in the summer of next year.