Kim Kardashian West bought bottom workout machines for her sisters.

The 'Keeping Up with the Kardashians' star purchased the DB Method machines for her family - including her siblings, Kourtney Kardashian, Khloe Kardashian, Kendall Jenner and Kylie Jenner, and her mother Kris Jenner - which promise to ''deliver fast, convenient, butt-blasting results''.

Taking to her Instagram stories, she said: ''I got my sisters and my mom a Christmas present but I got myself one too.

''I'm working out right now and I'm gonna open this and show you guys what I got them. I hope my sisters and mom will like this!''

Kim also showed her personal trainer Melissa Alcantara giving it a go.

She added: ''Melissa's testing it out. It's the DB method and this is what I got my sisters, all my sisters and my mom, for one of their Christmas presents. God I feel it in my butt a lot. They're getting them today.''

And Kris has already received her one, taking to social media to share her excitement at opening the gift just a few days ahead of Christmas.

Sharing a video of the machine and sharing her own reaction to the brand new fitness gift, which was wrapped in a huge red bow, she said: ''Kim, what in the world is in this huge box you just sent me? This box is as big as I am. Oh my gosh. Whoa Kim, this is so incredibly crazy. Is this a booty machine?''