Bruce Jenner has moved on from Kris Jenner and has been dating already.

According to People, the 64-year-old former Olympic star is reportedly dating Kris's former assistant and longtime friend Ronda Kamihira.

Kamihira, who is 51 and divorced, has two daughters, Maddy and Spencer, who are friends with the former couple's daughters Kendall and Kylie Jenner.

"Kris is devastated. This was her former assistant and best friend of 20 years," a source said.

"Kendall and Kylie grew up with her two kids and have been their best friends," the insider added.

On 4 October, Bruce was spotted with Kamihira, while attending Elton John's concert at Staples Center in Los Angeles.

The insider added that the 58-year-old Kardashian matriarch "is just shocked" that the two are dating and "she's so sad and completely heartbroken".

On 22 September Kris filed for divorce from Bruce, 11 months after they announced their split.

"This has got to be one of the biggest blows to Kris in her life. She feels completely duped by Ronda. It's complete and utter betrayal," a source told Hollywood Life.

"It hurts badly because Ronda was one of her best friends, especially when she was contemplating filing for divorce from Bruce. Ronda was also one of the first to know Bruce was moving out," the insider added.

Meanwhile, the Keeping Up with the Kardashians star had opened up about her separation on Beyond Candid With Giuliana.

"I signed up at the time for happily ever after and it didn't work out that way," she told Giuliana Rancic. "It makes me really sad."

"I feel like I failed at something because I wanted it to be that relationship for the rest of my life," she continued. "When I realized that it wasn't then you want the next best thing and that's an amazing friendship."