As bad first dates go, it's hard to top the one had by Wang Pai and a woman known as Lili.

The two met online and hit it off enough to meet in person in their home town of Muling City, China, for hot sex.

Trouble was, it was only when they met in person did they realize that Wang, 57, was the father-in-law of Lili, 28, according to the Daily Star.

To make matters worse, Wang's son, Wang Jai (or "Da Jun"), came home, saw the hook-up email on his wife's computer and followed her to the hotel in hopes of ruining the rendezvous -- not realizing he'd soon be running into his Dad.

The two had no idea of the other's identity when they decided to meet. Wang Pai had used a photo of a fellow army buddy, while Lili had used a fake picture and the name "Ming Chen" during their chats.

Naturally both were shocked when they first laid eyes on each other, Pai admitted.

"When I opened the door, I don't know if she was more surprised or me," Pai said according to Orange News.