R&B star John Legend had to ring in his 39th birthday in the sky after a flight nightmare en route to Japan.

The All of Me hitmaker had been planning to spend the day on vacation, but he and his model wife Chrissy Teigen suffered a serious delay on Tuesday night (26Dec17) after their Tokyo-bound plane returned to Los Angeles when a passenger was found onboard with the wrong ticket.

Chrissy, who is pregnant with the stars' second child, documented the bizarre incident in a series of posts on Twitter, revealing they had been four hours into the All Nippon Airways journey when the pilot announced they had to turn back.

They were eventually able to take off again, but the travel ordeal meant John had to celebrate the start of his birthday on Thursday (28Dec17) on the long flight, instead of on the ground in Japan.

Chrissy shared a photo of her man wearing a party hat onboard, and captioned it, "It's john's birthday here in the sky! Wish @johnlegend a happy birthday!"

They landed in Tokyo an hour later, when the beauty revealed they had decided to change their original travel schedule so they could take it easy in their return to the big city.

"We are HERE!," Chrissy declared. "We uhhhhh went ahead and canceled our connecting flight to nagoya and 3 hour car ride for...obvious reasons...but are happy to stay here in Tokyo! We feel like young lovers again. Been a while since the ramen adventures of 2012!"