Karlie Kloss has posted a heartfelt tribute to her boyfriend Joshua Kushner for his birthday.

The blonde beauty took to Instagram on Monday (12.06.17) night to post a picture of herself with her ''best friend'' and beau as the pair rang in the digital entrepreneur's 32nd birthday.

Karlie captioned the sweet snap: ''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)''

And the 24-year-old model's post comes as she previously said she takes a digital detox for one day every week, as she thinks it is very important to ''totally shut off'' from technology on a regular basis in order to connect with both herself and those around her.

She said: ''I will totally shut off and not post Instagrams or answer my emails. I think it's important to step away for a minute and actually reconnect with people and reconnect with yourself.

''We live at a very fast pace and sometimes you can lose priorities and perspectives.''

Karlie - who has been in a relationship with Joshua for five years - also insisted she is ''kind of old-fashioned'' in her choice of communication methods as she would rather interact face-to-face, despite being a prolific user of social media.

She said: ''I prefer to sit and have a conversation and feel present. As transformative and wonderful as technology is, at times I think being so absorbed in these online personas can make it hard to exist in the actual moment.''

But although she isn't always glued to her phone, she does like keeping the device nearby.

She added: ''I keep my phone pretty close to me.''