Liam Payne has joked he’d swap his popstar girlfriend Cheryl for an In-N-Out burger.

Fellow singer Sam Smith got Liam and Cheryl’s mouth watering after he posted a picture of himself tucking into one of the fast food restaurant’s famous burgers on Instagram.

Commenting underneath, Cheryl, who has 11-month-old son Bear with Liam, wrote: “the best burger there is!”

Not long after, cheeky Liam also commented.

“I think I would probably give you away for one of those right now... s**t!! Did I just type that out loud,” he posted in reply to Cheryl.

“good job I pressed the reply button as well @cherylofficial,” he added.

“I’m f**king useless at this thing.”

Ignoring the couple's banter, Sam told Liam the food was “GLORIOUS” and agreed with Cheryl that In-N-Out do the best burgers in the world.

Clearly craving one for himself, Liam continued: “Bring one home in your suitcase in fact no next time take me in your suitcase.

“next time I see you with one of those I’m going to rob you in public.”

Fans lapped up the 24-year-old’s jokey tone, though the exchange comes amid more speculation about the state of Cheryl, 34, and Liam’s relationship.

A source told British newspaper The Sun that the One Direction singer has been questioning his two-year romance with Cheryl while he’s been on the road touring his solo material.

“Up until now everyone has assumed it’s Cheryl who has gone cold on the relationship but it’s the other way around,” the insider divulged. “Liam appears more committed to a pop star lifestyle than becoming a real family man.

“He was very keen to marry Cheryl early on but she wasn’t up for it because of her two failed marriages. Since then he has been on the road, with Joan (Cheryl’s mum) spending more time at the house.”