The rapper pointed to Kardashian in the VIP box during a performance of his song 'Way Too Cold', Us Weekly reports.
The track, formerly known as 'Theraflu', caused speculation when it was unveiled in April as West rapped about his feelings for Kardashian before the couple were confirmed to be dating.
Referring to Kardashian's ex-husband Kris Humphries, the lyrics include the words: "And I admit I fell in love with Kim/Round the same time she fell in love with him/That's cool, babygirl, do your thing/Lucky I ain't had Jay drop him from the team."
West motioned towards Kardashian, who attended the gig in Atlantic City with her friend Jonathan Cheban, when he rapped those words.
West and Kardashian have recently made a number of public appearances, including attending the BET Awards with Jay-Z and Beyoncé and visiting a children's hospital in Los Angeles.
West will make his debut in Kardashian's reality show Keeping Up With The Kardashians in the episode due to air tonight (July 9) on E!.
Watch Kanye West performing 'Way Too Cold' in Atlantic City below: