Rob Kardashian
Rob Kardashian, photographed at the 2012 Miss USA Competition in Las Vegas, Nevada, has been working out with his sister Kim Kardashian. Getty Images

Rob Kardashian has really upped his Instagram game as of late. The Arthur George sock designer has chosen to withdraw from the public eye — both in person and online — for the better part of the last few years. But he has resurfaced on Instagram and Twitter several times in the past couple of months. Kardashian, 28, shared yet another photo Monday, this time featuring one of his famous siblings and her rumored beau.

The former "Keeping Up With the Kardashian" star posted a photo of sister Kylie Jenner and rapper Tyga on social media. According to the caption, the shot was taken that morning as the could-be-couple headed out for their "morning workout." The photo showed Jenner, 18, rocking a sports bra, leggings and sneakers while Tyga, 25, flashed a little thigh in black sweat shorts and a matching black shirt.

This is just one of many photos Kardashian has shared since returning to Instagram on July 31 with a shirtless throwback photo. Since then he has shared numerous photos, including two stills from the 2006 film "Miami Vice," a screen grab of a tweet about him from sister Kim Kardashian West and a photo of Kanye West kissing daughter North West on the cheek.

Although Rob has not been seen for a majority of the last few years, his sisters, especially Kim and Khloé Kardashian, have been sure to keep the public up to date on their little brother's life. During an interview with Complex for their August issue, Khloé, 31, revealed that she and Rob are currently living together. She added that although her brother occasionally gets down on himself for living with his sister she always makes sure to bring him back to reality. Similarly Kim, 34, shared with Rolling Stone magazine on July 1 that she's come to terms with the fact that her brother "feels uncomfortable" being in public right now. She revealed that in his free time he "smokes weed, drinks beer, hangs out and plays video games with his friends," adding that it could be much worse.

"It's not like hookers and meth at the Ritz," she said.