Fans were quick to complement Robs new slimmer physique.
‘Rob your looking great, keep up the hard work,’ one fan commented on the pic.
Another wrote, ‘Rob, you look amazing!!! So happy to see you happy with your daughter!’
Rob, who has previously struggled with his weight, is well known for his late night snacking and binge-eating but the reality star is looking healthy, happy and fit.
Rob celebrated his 31st birthday at his mother, Kris Jenner’s house, with several members of his family.
And, his famous sisters aren’t the only ones who gave rob a shout out for his birthday. His ex-fiance, Blac Chyna also shared a birthday message on social media, despite their tumultuous history. ‘Happy Birthday Rob from Dreamy and Chy,’ she wrote.
The couple have decided to amicably coparent after Rob went on a social media rampage against Blac, posting explicit images of the former reality star and accused her of cheating on him.
Chyna later filed a restraining order against him and is currently seeking legal action against members of the family over the cancellation of her show, Rob & Chyna.