The 25-year-old presenter admits her friends find it "weird" that she and Luke Worrall, 20, do everything together, but insists they miss each other too much when they are separated.
She said: "We don't do anything separately. We do absolutely everything together. And a lot of people think, 'God that's a bit weird – you're so young and you do everything together.' But when we try to do things separately, we just find ourselves texting each other and end up meeting up because we don't like it."
Despite their closeness, Kelly is in no rush to marry Luke because she doesn't see the point.
Kelly - who she has been dating for over two years - explained to heat magazine: "For me, marriage is just a certificate. As far as I'm concerned, Luke's the love of my life and that's all that matters."
Although they are inseparable now, Kelly had to work hard to make Luke interested in her.
She said: "I had a huge crush on him but I don't think he liked me when we first met. He grew to love me!"