Khloé Kardashian and NBA star James Harden are rumored to be getting serious, with the Houston Rockets star even starting to wonder if she may be "the one."

Hollywood Life reports Harden is now "deep in love" with Lamar Odom's ex-wife and is even ready to start a family with the 31-year-old "Keeping Up With The Kardashians" star.

"James has promised Khloé that he will be the one that will be her 'baby daddy,'" a source told the website, adding that Harden is "all in for this relationship."

And more and more, the two are going public with their growing closeness. Harden recently accompanied Kardashian to sister Kylie's 18th birthday party, and at the end of the night, the two left in the same vehicle. When they were also recently spied partying together in Houston, reports are they could not keep their hands off one another.

Kardashian also recently threw her new beau a lavish birthday bash, where sisters Kim and Kylie joined in the celebration, as did their men, Kanye West and Tyga. Part of the night's festivities was an elaborate fireworks display, but sources joke the show paled in comparison to how electric Harden and Kardashian's relationship appears to be.

But the 35-year-old Odom appears to still have the hots for his ex and recently warned not to count him out.

"He's probably wasting his time," he told InTouch magazine of Harden, in what was described as a "rambling interview." Odom referred to Kardashian as his "soul mate."

Kardashian and Odom were married for four years before she filed for divorce in late 2013. The proceedings languished for more than a year before recently being finalized. At the time of their split, Odom was rumored to be hooked on drugs and cheating on his wife.