Game Of Thrones: 10 Most Believable Fan Theories

As seen last season, when Cersei was a child she found Maggie the Frog after hearing of her magical powers, and forced her into prophesying her future. She asked if she would marry the Prince - hoping for a betrothal to Rhaegar - but was told she'd instead marry the King. This was true when she married King Robert. 

She asked if they would have children, and was told six-and ten for him, three for her, with golden crowns. Again, this has come to pass: Robert had a number of bastards, while Cersei had three children to Jaime, all of whom were golden haired like herself, and two so far have worn an actual crown. 

She also stated their shrouds would be gold, indicating they would all die before her. So far, Joffrey and Myrcella have been killed, so Tommen needs to watch his back. The final part of the prophecy was that, after her children are dead, "the valonqar shall wrap his hands about your pale white throat and choke the life from you."

Valonqar is the High Valyrian word for 'little brother', which Cersei takes to mean that Tyrion will be the one who tries to kill her. However, her twin brother Jaime was born just after her, meaning he too could be considered 'little brother', and is therefore a candidate to be the valonqar. Given the way their relationship has gone, it wouldn't be too much of a stretch to imagine Jaime strangling his sister to death, and most poetically with his golden hand.