Looks like this holiday season was a rocky one for Robert Pattinson and his rumored fiancée, FKA twigs!

According to a new report, the singer, 27, was furious when she learned that her beau, 29, was secretly talking to his ex-girlfriend and Twilight costar Kristen Stewart, 25, behind her back!

RELATED: Kristen Stewart Opens Up About Her Sexuality

kristen and robert

Even though the source tells OK! magazine that the songstress is “not the jealous type at all,” she was still allegedly “enraged” to discover K. Stew’s name in her man’s recent calls.

“She confronted him about it straight away and he insisted it was just a good-will congratulations call about Kristen being in the Oscar race this year,” the source says. “[FKA twigs] is not happy at all about this and isn’t really satisfied with his explanation.”

robert and fka

The Twilight costars dated for years, only to call it quits in 2012 when she was caught having an affair with a then-married man, Rupert Sanders.

RELATED: See What the Cast of ‘Twilight’ Looks Like Today!

The source adds of Rob’s infatuation with his ex, “[FKA twigs] knows how hung up Rob was on Kristen and how hard it’s been for him to move on, so the fact that he’s gone and done this has totally unsettled her.”

Do you think this is the end for Rob and FKA twigs?

Have a tip? Send it to us! Email In Touch at contact@intouchweekly.com.