SOPHIE SETTING JOE'S HASH WITH TELL-ALL PAGE-TURNER!

RUTHLESS Game of Thrones vixen Sophie Turner is planning a scandalous tell-all about her soon-to-be exhusband Joe Jonas - and the singer's former flame Taylor Swift is providing plenty of extra ammo, sources squeal.

After the hitmaker filed to end their four year marriage, Taylor allowed Sophie, 27, and the estranged couple's daughters - Willa, 3, and Delphine, 1- to use her NYC apartment. The grownup gals have been spotted out on the town as insiders suggest they're planning Sophie's divorce strategy.

"They're spending lots of time together and have a ton of stories to share about Joe," dishes an insider. "It's kind of fun for them to let  it rip-outside of the kids' hearing range, of course."

The spy snitches the Bad Blood songbird, 33, still holds a grudge against the Jonas Brothers hunk, 34, for dumping her more than 15 years ago with a 27-second phone call!