Awkward alert!

Kourtney Kardashian stepped out to grab a sushi lunch with her son Mason yesterday in Calabasas, and our videographer had the guts to ask her about Justin Bieber's recent engagement to Hailey Baldwin. Why is that weird, you ask? Well, the mother-of-three and JB used to hook up from time to time before she got together with boy toy Younes Bendjima!

Of course, she chose to say nothing, but it's gotta be a little uncomfortable for her! After all, her little sisters Kendall and Kylie are besties with Hailey, and the model probably knows their 39-year-old sibling used to sleep with her future hubby. Kourt shouldn't bank on getting a wedding invite, even though she's reportedly still on friendly terms with The Biebs!

The eldest of the K clan probably isn't crying over it, though, because she's having too much fun with her current beau... between the sheets!

“Younes loves being with an older woman because Kourtney is more experienced and more comfortable with her body than any other woman he has ever been intimate with. They have great chemistry together, and it’s fireworks every time they step into a bedroom together,” a source told Hollywood Life.

Other than Demi Moore, Kourtney K is the original cougar!