The 46-year-old country musician and his actress wife have to spend a lot of time apart because of their busy careers and so have found ways to keep the romance alive in their relationship when they can't be together.
Keith - who is a judge on 'American Idol' - says he and Nicole, 46, prefer to keep in touch with phone calls but on occasions they can't resist sending each other naughty messages and photos.
During an interview on 'The Ellen Degeneres Show', he stuttered as he confessed: ''We never text, we never email. Phone calls only, which I really love. Well, maybe one text. Maybe one cool kind of, you know ... one of those kinds of texts, yes, one of those ones with the accompanying photo. One of those kind of texts.''
Ellen then pushed him to reveal what kind of message he was talking about, asking: ''What kind of text? What do you mean?''
To which Keith replied: ''Nice sex texting. I'm a little red right now!''
The couple - who have two daughters, five-year-old Sunday and Faith, two - have been married for seven years and have homes in Sydney, where Nicole grew up, Los Angeles and Nashville.
They have been spending time apart recently as Nicole has been in London shooting a new movie, while Keith has been touring the US for 'American Idol', but the 'Stupid Boy' singer insists he and the screen beauty are good at organising their life together.
He said: ''We just make it work.''
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