Rob Kardashian is getting out of the house and working on his fitness.
The reclusive Keeping Up With the Kardashians star revealed on Instagram that upon venturing outdoors for a workout, he came across his sister Kylie Jenner and her reported boyfriend Tyga.
WATCH: Kris Jenner Worries Rob Kardashian Is 'Going to Die,' Says He's Gained 100 Pounds In the Last Year
"Spotted these fools on the morning workout," he captioned an Instagram pic of the youngest Jenner sibling and the rapper.
It appears to be the summer of health for Rob. Earlier this month, Kim Kardashian revealed that she was working out with her 28-year-old brother. "Just went on the hardest hike ever today with @robkardashian," she tweeted on August 14.
Kim also tweeted on Tuesday: "Rise & Grind! Workout time!!!!! With @robkardashian."
Rob currently lives with his older sister Khloe Kardashian in her Calabasas, California home, and according to Khloe, she wouldn't have it any other way.
MORE: Rob Kardashian Calls Out His Haters -- 'Yes, I'm Fat Now'
"Rob lives with me now and I wouldn't have it any other way. I love having him with me," the 31-year-old reality star told Complex magazine. "He's going through a hard time now and it's behind gates. With this crazy lifestyle you have to think of places where you can still have your freedom."
WATCH: Khloe Kardashian -- I Call Rob My Son As a Joke
Rob is rarely seen out in public but in June, ET obtained photos of him making a late-night food run at In-N-Out Burger in Woodland Hills, California. Here's a look at Rob's rare outing: