'DWTS' Love Triangle! Amber Rose At War With Maksim's Pregnant Fiancee

Amber Rose is seriously sexy, and it's not just Julianne Hough who's noticed! RadarOnline.com has learned that Peta Murgatroyd, the pregnant fiancée of Rose's Dancing with the Stars partner Maksim Chmerkovskiy, is keeping a close eye on the former video vixen.

"Peta does not seem happy about how close Maks and Amber have become," a source close to production for ABC's hit celebrity dancing competition told RadarOnline.com exclusively.

According to the source, Murgatroyd, 30 — who led deaf-contestant, Nyle DiMarco, 27, to last season's victory — had been attending her future husband's rehearsals with Rose, 32, to keep watch, until she was told that she could no longer come!

"It seemed to make Amber really uncomfortable having Peta there watching her rehearse with Maks," the insider said.

Last Sunday, Murgatroyd put on a brave face when she attended Rose's Slut Walk event in L.A. with Chmerkovskiy, 36.

But according to the source, after the event, "Peta's jealousy got even worse because she saw how close Maksim and Amber really are."

"Amber and Peta are complete opposites and Maksim loves Amber's energy and how carefree she is," the source told RadarOnline.com.

"People on set just think that it is Peta's hormones that is causing her to freak out," the insider said, adding, "She really has no reason at all to worry about losing her man to Amber."