Karlie Kloss admitted she has ''never felt more happy in my own skin'' as she celebrated her 26th birthday on Friday (03.08.18).

The stunning model told her 5.98 million followers that the past year had been the best of her life and that she is ''excited'' about the future, which will see her tie the knot with her fiancee Joshua Kushner.

Alongside a photo of her holding two foil balloons in the shape of 26, she gushed: ''25 has been one of the most extraordinary years of my life. I have truly never felt more happy in my own skin and energized and excited for the future I want to build. I am so grateful for your love and support...I have a feeling 26 is going to be the best one yet ;)[sic]''

The blonde beauty and her beau have been dating for six years, and finally took the next step in their relationship recently when Joshua got down on one knee to ask the her to marry him.

Posting a picture of herself kissing Joshua on the cheek on Instagram last month, Karlie wrote: ''I love you more than I have words to express. Josh, you're my best friend and my soulmate. I can't wait for forever together. Yes a million times over (sic)''

The post was accompanied by a ring emoji, signalling the pair had gotten engaged.

According to sources, Joshua proposed to the Kode with Klossy founder earlier that month during a romantic getaway to New York, and the pair were believed to be ''overjoyed'' with happiness.

An insider said: ''He proposed a few weeks ago during a romantic weekend together in upstate New York. They're both overjoyed and happily celebrating. Their hearts are full and they're excited to build their future together.''

Karlie and Joshua have remained mostly private about their romance since they began dating in 2012, but the beauty previously revealed she was ''definitely not planning on falling in love'' with him and that she feels love is best when it is spontaneous as it is one of those things that you ''can't anticipate or plan''.

She explained: ''I was definitely not planning on falling in love. But I think that's the thing about it, you can't anticipate or plan it.''

Last year, to celebrate five years together, Karlie posted a sweet tribute to her long-time partner on social media.

She wrote: ''My atoms love your atoms, It's chemistry. - @atticuspoetry Happy birthday to my best friend and partner in crime. The past 5 years of our adventures together have been some of the best memories of my life. I love you @joshuakushner [sic]''