There's nothing blurry about the line between Robin Thicke and Miley Cyrus these days. Thicke, 36, is angry with Cyrus, 21, for "going too far" with that infamous foam finger during their August 2013 MTV Video Music Awards performance, a source shares in the new issue of Us Weekly.

"Robin is jealous Miley's career took off after that," a second insider tells Us of the "Blurred Lines" singer, who was criticized for being "old enough to know better" in the wake of their headline-making duet. "He thinks she hijacked the performance." 

The "Wrecking Ball" songstress, meanwhile, resents Thicke for not defending her after the show. (Asked about the pop star's racy moves in an interview with Oprah Winfrey, the Grammy-nominated crooner replied, "That's on her.") "Miley thinks Robin threw her under the bus," the source says.

Another insider denies there's bad blood between the two, but as one eyewitness noted at Clive Davis' pre-Grammy party on Jan. 25, they weren't exactly rushing to greet one another. "They were just a few tables apart and never spoke," the onlooker said.

For more on the duo's post-duet tension, watch this week's Hot Stuff video, as explained by Us Weekly entertainment director Ian Drew and Dancing With the Stars alum Karina Smirnoff.

Other stories in the roundup: Josh Lucas' sudden split; Khloe Kardashian and Kaley Cuoco's real estate trade; and much more!