Originally published on ProWrestlingSheet.

Wear your pajamas to work day might get real awkward for John Cena ... because the United States Champ says he prefers to sleep in the nude.

Cena was a guest host Monday on The Today Show when he revealed the naked news to his co-host -- after she questioned whether he wears pajamas to bed.

The co-host claimed to have asked Nikki Bella for permission before inquiring ... but after John told Jimmy Kimmel he used a stunt penis for his role in Trainwreck, this would seem tame.