The ongoing custody battle between Joe Jonas and Sophie Turner is about to reach new heights, similar to the epic battles featured in "Game of Thrones."

Reports indicate that a full-blown war may be imminent.

Those close to the actress, who gained fame as Sansa Stark on the HBO phenomenon, are claiming that she is preparing to take a stand after her ex-husband publicly attempted to portray her as an irresponsible parent following their divorce.

An inside source revealed to The National Enquirer that, according to them, Joe had seriously underestimated Sophie, explaining that she is now out for vengeance due to this misunderstanding and wishes to demonstrate her power in breaking down his perfect public image.

Just days ago, it became public knowledge that Sophie and Joe had decided to start a four-day mediation process to reach an agreement about the end of their relationship and decide on custody matters for their two daughters, Willa (three years old) and Delphine (one-year-old). Lawyers representing both parties have since confirmed the news.

The push for the end of Joe Jonas and Sophie Turner's four-year marriage reportedly came to a head when he overheard her seemingly badmouthing him to a friend. Sources said this was not the only factor, though it did tip the scale for the boy band singer.

Joe has decided to seek joint custody of his daughters since submitting the divorce papers in Miami on September 1.

Those familiar with the couple's situation reveal that Turner had been frequently absent, leaving him as the sole caretaker for their two girls.

READ ALSO: Joe Jonas, Sophie Turner Unleash Their Individual Smoking Guns Amid Messy Divorce Battle

Subsequently, it was alleged by Sophie that her former husband did not surrender their children's passports, which would have allowed them to travel back to England along with her following an international child abduction law.

She has requested that the divorce proceedings be held in her homeland of the UK, a petition which Jonas labeled as "particularly concerning and problematic."

In the run-up to the mediation, Joe and his ex-wife acknowledged that they would keep their children in New York until a settlement is reached.

An observer close to the case reported, "Joe seems rather out of spirits these days, but he's standing his ground."


READ MORE: Joe Jonas, Sophie Turner Divorce: Here's How Taylor Swift Plays Major Role In A-Listers' Split

Join the Discussion