Kourtney Kardashian defends sister Kim after fans accused her of posting ... trends now

Kim Kardashian took to Instagram on Thursday to mark her sister Kourtney's 45h birthday with a bikini snap that left fans divided.

The SKIMS mogul, 43, shared a photo of her with Kourtney and younger sister Khloe, 39, as they splashed in the ocean wearing matching black bikinis, taken on their recent getaway to Turks and Caicos.

The snap caused a stir, with many claiming Kim intentionally picked a photo in which she looked the best, while many others praised Kourtney's postpartum figure, calling her the most 'natural looking' of the sisters. 

Kourtney — who gave birth to son Rocky roughly five and a half months ago — didn't seem to mind and responded underneath a comment which read, 'Now you know she's not going to like this photo... lol it's her bday Kim... lol.'

The mom-of-four wrote back, 'I LOVE this photo! It is me and my sisters having the best time on a trip with our kids... and the memories to last forever! And I LOVE this body that gave me my 3 big babies and my little baby boy.'

Kim penned a sweet caption to her sister underneath the snap, writing, 'Happy Birthday Queen.'

'There's no one on this planet that I have spent more time with and have all of the same memories with growing up than you and I cherish them all. 

She went on, 'Sharing a room and friends and cars and our lives together for four decades has been the most magical journey to have you by my side.'

'I love you and I can't wait for another 45 years together! I will especially cherish this last sister trip where all of our kids had dance parties til they passed out, the way we all did growing up!'

'Celebrating you today and grateful to you forever for always giving the best advice a sister could possibly give!'

Kourtney — who once called Kim a 'witch' — was touched by the tribute, writing, 'This caption [heart emoji] I love you sooooo and so grateful for all of the incredible memories we have together… when I think it, it’s like a movie plays in my head of all of them! So blessed!' 

Her husband Travis Barker, 48, also left a heart emoji on the post. 

After Kim made her tribute, a number of fan comments poured in, questioning the choice of the 'shady' photo. 'Well this was intentional,' one person wrote.