The couple was rumoured to be dating earlier this month when they were spotted jetting off to Cabo San Lucas in Mexico over America's Labor Day weekend, and later at Drake's concert in Los Angeles.
Now, the 32-year-old reality star has addressed the rumours head on, and posted a steamy clip on Snapchat on of her kissing the 25-year-old sports star, reported Us magazine.
The couple was partying in Miami, Florida, with Khloe's older sisters Kim Kardashian and Kourtney Kardashian after Kanye West's gig at the AmericanAirlines Arena.
Before the show, a newly-blonde Khloe was seen holding hands with the Cleveland Cavaliers player as they joined Kourtney and family friend Jonathan Cheban at Zuma Miami for dinner.
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Khloe has reportedly been single since splitting from another basketball player, James Harden, in February. She was also previously married to another former basketball player, ex Los Angeles Lakers sportsman Lamar Odom.
The couple split in 2013 but put their divorce on hold when Lamar was hospitalised after being found unconscious in a Nevada brothel last October.