Zayn Malik and Gigi Hadid have "private" nicknames for one another.

Gigi Hadid and Zayn Malik

Gigi Hadid and Zayn Malik

The 'Pillowtalk' singer and his model girlfriend usually address one another by the first letter of their names, but they also use other terms, which the former One Direction star isn't so keen to share with the world.

He said: "I call her Gee, she calls me Zee. There's some other nicknames too, but I'll keep those private."

The couple have been living together in Los Angeles for "this past year", and though the 24-year-old singer has introduced Gigi, 21, to his family, he hasn't yet taken her back to his home town of Bradford, West Yorkshire, North England.

He told Sunday Times Style magazine: "I've never took her to [my hometown] Bradford, not yet. She's met my family in London a few times, though."

Earlier this month, the 'Like I Would' singer decided to surprise Gigi while she was in France for Paris Fashion Week.

However, he accidentally gave the game away, but the blonde beauty still "played along" with his romantic gesture.

He said: "She didn't know I was coming. I went up to the suite to knock on the door...But my number had changed to European on her phone, so it wasn't much of a surprise in the end. She played along with it, though."

But Zayn was glad he made the trip as the couple had an "amazing" time.

He said of being in Paris: "It's been amazing spending time here with my girlfriend."

Gigi recently opened up about she met the 'I Don't Want to Live Forever' singer, admitting that despite trying not to give too much away on their first date, she struggled to keep it together as the pair "connected really quickly".

She said: "We actually met at a friend's birthday party a few years ago. Then, he was in New York to come to the Victoria's Secret show... and ended up not coming.

"I was like, 'I'll play it cool, I'll go to the after party.' He wasn't there. And then later that week, we ended up going on our first date.

"We played it cool for like ten minutes, and then I was like, 'You're really cute.' We connected, like, really quickly."