The Keeping Up With The Kardashians star shared an image on Thursday, 25 June, showing her ridiculously adorable young son looking somewhat bemused by the camera.
Reign was born on 15 December last year but unlike his siblings Mason and Penelope, has not been featured on the family reality shows or seen in public that often.
The tot also missed out on the family trip to Disneyland last week in honour of cousin North West's second birthday.
Kourtney took Mason, five, and Penelope, two, to the California theme park to spend the day with sister Kim Kardashian's daughter North and other friends last week.
Perhaps partner Scott Disick was on babysitting duties?!
Meanwhile, while Kourtney hung out with friends in LA, her mum Kris Jenner and sister Kim have been attending a creativity conference in France before flying to the UK ahead of Kanye West's headlining performance at Glastonbury tomorrow.
All you need to know about Kourtney Kardashian: