He’s got his eyes on the prize(s)! Tristan Thompson couldn’t stop staring at girlfriend Khloé Kardashian’s cleavage while attending Kylie Jenner’s surprise 20th birthday party on Wednesday, Aug. 9 — and Kim Kardashian totally caught the adorably awkward moment on Snapchat.

As seen in Kimmy’s snap, the hunky basketball star, 26, was totally enamored by KoKo’s enviable curves, which she flaunted in a sexy LBD with a plunging neckline. And judging from the pic, Khloé, 32, didn’t mind Tristan’s glance whatsoever. As he took in the view, the Strong Looks Better Naked author faced her gaze toward the floor and flashed a slight smile as her right hand rested in her beau’s lap.

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The couple’s PDA display comes just days after an insider exclusively told Life & Style that Tristan is getting ready to ask for Khloé’s hand in marriage next month. “They’re talking about getting engaged by September,” an insider said of the couple, who started dating in August 2016. “Tristan has asked her sisters what kind of ring she’d want. He’s planning a very romantic proposal.”

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❥ իմ սեր ❥ Im ser ❥ All my Love ❥

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Obviously, Khloé (who finalized her divorce from Lamar Odom in December 2016) would say yes. As she revealed earlier this year on an episode of Keeping Up With the Kardashians, she is hoping to settle down again — especially because she can’t wait to start a family with Tristan.

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“He wants to have five or six kids with me and that’s lovely,” she said of the NBA champ, who is already dad to a seven-month-old baby boy named Prince, whom he welcomed with ex-girlfriend Jordan Craig last year. “We could start at one and grow from there.”

To see Khloé and Tristan’s cutest moments to date, click through the gallery below!