UPDATED: Khloé Kardashian reportedly ambushed by Lamar Odom

A witness says they saw the heated exchange outside a Soul Cycle class in Beverly Hills.

TMZ reports that Khloé Kardashian was involved in a heated exchange with her ex-husband, Lamar Odom early Wednesday morning.

A witness claims to have seen Khlo outside her morning Soul Cycle class at 6.45am, when Lamar appeared out of nowhere and “launched a verbal attack,” demanding that she talk to him.

Khloé reportedly yelled at him, "How did you know I was here?" although he failed to give a clear answer.

The witness also said Lamar tried to touch Khloé’s arm and she yelled at him, "Get off of me, get off of me! Stop! Stop!"

According to TMZ, Khloé was so upset that she threatened to call the police, to which Lamar responded, "You're not going to call the cops on Lamar Odom."

The witness said she looked visibly shaken and left immediately in her car.

People magazine now report that the spat may have been because Lamar has issues with Khloé’s new relationship with NBA star, James Harden.

"Lamar has been trying to contact Khloé, but she is done and has ignored him. Lamar has issues with Khloé dating [James]." the source said. "It made Khloé first shocked and then scared that Lamar was waiting outside the studio."

The magazine also claims Khloé has changed her number several times to avoid Lamar.

The pair married in 2009 and Khloé filed for divorce in 2013, although their split was only made official in July this year.

Khloé opened up about her relationship with Lamar in the September issue of Complex magazine, admitting that she missed him “every day.”

“I talk to Lamar as often as I can, which is inconsistent, but not on my terms,” she said.

“Lamar is genuinely one of the best people I’ve ever met, and everyone says that when they meet him. I think Lamar’s gonna always be that person [for me] but that’s what made it so special.

“Even if I had it for five years or whatever, it was the best ever and I’m grateful I did. Some people don’t get that ever and I had that magic for a long time.”

BRB, sobbing.

UPDATE 14.08:

TMZ have spoken to a visibly upset Lamar Odom and filmed it (real nice, TMZ) and he has denied that he ambushed Khloé, instead claiming their meeting (at 6.45am) had been pre-arranged.

"Nobody got grabbed on," he said. "I am not, not, not the person that they're trying to make me out to be."

"The dog has to fight back​."

Lamar added that he’s "hurt that [Khloé] is not standing up for him" and that he would "air everything out" if this kind of thing continues.

However a “source close to Khloé” has since told E! News that she made no plans to meet Lamar and the whole thing was “very upsetting.”

"She has been trying to move on but he is not allowing that to happen," they said. "What he did crossed the line."