Lady Gaga is known as 'Lady DullDull' among her tour crew.

The 'Alejandro' singer - real name Stefani Germanotta - is well-known for her outlandish stage outfits but is said to prefer a more comfortable look when she is off-duty, opting for baseball caps and sweat pants.

A tour insider explained to National Enquirer magazine: "She gets all comfy in sweats and a baseball, then becomes the easygoing gal we jokingly call 'our den mom'. Another nickname we have for her is 'Lady DullDull', because she looks just like any one of us.

"And Stefani's sweet as a Jewish mom, always mediating and offering advice on the crew's dating problems, family issues, or whatever. She not only listens to everyone's problems, she gives really great advice on how to fix them."

In the past, the kooky star has revealed she thinks it's important to maintain her public persona at all times.

She said: "If I were to ever, God forbid, get hurt onstage and my fans were screaming outside of the hospital, waiting for me to come out, I'd come out as Gaga. I don't even drink water onstage in front of anybody, because I want them to focus on the fantasy of the music."