Rob Kardashian made a rare public appearance this week to support his new girlfriend, Blac Chyna, during her sexy bikini photo shoot for 138 Water by DRE in Los Angeles. 

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An eyewitness told ET that Rob was "sweet and so humble" at the shoot, while noting that the couple was constantly smiling and laughing. "The two definitely have a connection," the source said, adding that the two seem very comfortable with one another.

The photo shoot comes just one week after the 28-year-old reality star reportedly drove to Texas to pick up Chyna, who was arrested on public intoxication and drug possession charges in Austin.

For her part, the 27-year-old model rocked her beach-side shoot, sporting a skimpy red-and-black bikini.

While supporting Chyna's latest endeavor, Kardashian admitted to the eyewitness that he was "not in the best shape and it was time to shave."

The sentiment falls in line with a newfound focus on fitness, which Chyna’s pal, Amber Rose, says has been inspired by Kardashian's lady love. "They're working out. Chyna's cooking healthy meals for him," the How to Be a Bad Bitch author revealed. "It's a really, really good vibe."

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In December, Kardashian was reportedly hospitalized for diabetes, and sources tell us he has already started losing weight since returning to the gym.

Check out the newly clean-shaven and smiling Kardashian in the video below.