The "Kocktails With Khloe" host and the Houston Rockets star have split, according to several reports out Tuesday.
A rep for Kardashian did not immediately respond to The Times' request for comment.
Kardashian "dumped him two weeks ago," Us Weekly sources said.
The split news comes on the heels of January reports that Harden hit up a strip club with rapper Tyga, who has been dating Kylie Jenner. The sighting was linked to a cryptic tweet from Kardashian warning followers to "Stay away from people who make you feel like you are hard to love."
The "Strong Looks Better Naked" author, 31, has been linked to the bearded ballplayer, 26, since July, and they were seeing each other even when she called off her long-running divorce from Lamar Odom after he was found unconscious in a Nevada brothel in October.
Kardashian explained her unusual predicament on "The Ellen DeGeneres Show" in November and told People that Harden had been great with her and that she was "just allowing everything to unfold." She also noted that she would understand if her current situation got too overwhelming for Harden.
The reality star moved Odom from Cedars-Sinai Medical Center in Los Angeles to a live-in rehabilitation center in January, and she's said to have since moved him into a home closer to her Calabasas digs. She and older sister Kim Kardashian West live-streamed a Super Bowl Sunday group hike that included the former NBA star, indicating that he was progressing in his recovery.
But the reality star wasted no time putting herself back on the market after news of the Harden split broke Tuesday, sharing her newly minted OKCupid profile on her app and website.
"I've never done online dating before, but just for ... giggles, Malika [Haqq] and I decided to fill one out," she wrote. "It was actually really fun to do, LOL!"
She also hit the town Monday with her ex, rapper French Montana, and several friends to celebrate pal Dorian Renaud's birthday at BOA Steakhouse in West Hollywood, according to E! News, whose network airs her family's reality series.
The former pair also showed up at the Ace of Diamonds strip club, which happens to be the same establishment that Harden was spotted at last month, TMZ said.
Her appearance with the rapper prompted rumors that the two were rekindling their abbreviated romance, but E! said their relationship is "purely platonic" and they remain friends despite their 2015 split. However, sources also told the site that the "I Luh Ya Papi" emcee "still loves her" and would get back together "in a second if she would be willing to give it another shot."
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