We’re all pretty used to seeing Kim Kardashian’s trademark pout staring out at us from magazine covers, but have you ever wondered why the reality star doesn’t crack a smile too often?

See I do smile... even laugh on occasion. Not too often though because it causes wrinkles @shammaurice

Een foto die is geplaatst door Kim Kardashian West (@kimkardashian) op


Well Kim shared her reason for the straight face on Instagram, after posting a picture with her friend Shamari Maurice."See I do smile... even laugh on occasion. Not too often though because it causes wrinkles," Kim wrote beside the black and white pic.

More: "Style Icons" Kim Kardashian & Kanye West Are The New Faces Of Balmain's New Menswear Campaign [Pictures]

Of course Kim is most likely joking (at least we really hope she is) but after looking at the picture we’ve got to say, Kim you really should smile more often. The mother of one looks radiant as she shares a laugh with her friend in the photo booth at the Kardashian family's Christmas party.

But what did Kim and the rest of the Kardashian clan get up to over the festive period? Well judging by Kim’s Instagram it was a true family affair, as she shared pictures from mother Kris’s annual Christmas eve party.

More: Kim Kardashian Criticises Kris Jenner's Wardrobe: "I Love You Mom But No More Pilgrim, Addams Family Outfits'

At the party North West was introduced to Santa for the first time, however it appears the world’s most stylish baby hasn't yet warmed up to the bearded man in the red suit.

"North is still warming up to Santa," Kim captioned the picture. "The same Santa has come to my moms Christmas Eve party since I was a kid. I love sharing the tradition with my baby girl! Hope everyone had the best Christmas."