Karlie Kloss and Joshua Kushner are engaged.

The 25-year-old model and her long-term partner 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 blonde beauty to marry him.

Posting a picture of herself kissing Joshua on the cheek on Instagram on Tuesday (24.07.18), 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 have gotten engaged.

As of the time of writing, Joshua has not confirmed the news on his own Instagram account.

According to sources, Joshua proposed to the Kode with Klossy founder earlier this month during a romantic getaway to New York, and the pair are ''overjoyed'' with the news.

The insider told People magazine: ''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 beau 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)''