Princess Myrcella is the second child and only daughter of Cersei Lannister and Robert Baratheon (although she is actually be fathered by Jaime Lannister). She is described as a sweet, gentle girl who was close with her brother Tommen growing up.
In scenes with the Starks at Winterfell and Sansa and Tyrion at King’s Landing, Myrcella reveals herself to be a guileless and innocent girl, oblivious of the political machinations of her family. During the War of the Five Kings, Tyrion sets up a political marriage for Myrcella with Dorne, arranging for her to be married to Prince Trystane Martell when they come of age. Cersei is furious but unable to undo the plan. As part of the alliance terms, Myrcella is shipped away to live in Dorne until her marriage.
When Oberyn Martell of Dorne visits Kings Landing, Cersei asks to know how Myrcella is doing. Oberyn replies that the last time he saw her, she was playing happily in the Water Gardens at Dorne and that they “do not hurt little girls in Dorne”. Cersei asks him to deliver a message to Myrcella on her behalf – that her mother misses her very, very much. Cersei also prepares a gift to be sent to her daughter as a belated namesday present, a ship that the best shipwrights have built, since Myrcella loves the open water.
Myrcella Baratheon is played by Aimee Richardson and is a supporting character in Seasons 1 and 2 of Game of Thrones.