Shocking Photo : Bruce Jenner is dating Kris Jenner's Best friend

Bruce Jenner is dating Kris Jenner's Best friend 

Bruce Jenner is dating one of Kris Jenner's best friends of 20 years and former assistant.. 

From TMZ...

"Bruce has hooked up with Ronda Kamihira ... a 51-year-old mother of 2.

We're told Kris is "extremely upset" that Bruce is dating Ronda, and -- as one source puts it -- "It really stings because Ronda never told Kris she started seeing Bruce."

And get this ... for years Ronda and the Jenners have been neighbors in Hidden Hills, CA, even spending holidays at each others homes.

A Jenner source tells us the talk in family was that Ronda was weirdly becoming "Kris' single white female."  The source says Ronda mimicked Kris right down to her hair.

The pic was taken at Staples Center in L.A., when Bruce and Ronda went to Elton John's concert