The stunning singer - who is due to give birth to her first child with husband Jordan Bratman early next year - appears on the front cover wearing a cut-off leather jacket to cover her modesty, before stripping to just a pair of sexy Christian Laboutin heels for the inside pages.
The 26-year-old 'Dirrty' singer revealed in the accompanying interview she found out she was expecting on her 'Back to Basics' tour.
She said: "We were planning on starting to try after the tour. And so, I had gone off the contraception pill to prepare my body, because I didn't know how much time it would take.
"We had heard it can take some time - but with 'Power Egg' and 'Super Sperm' here that wasn't a problem. I just can't believe it happened so quickly!"
Christina also revealed she was so "paranoid" about hurting her unborn baby during her tour she decided to wear a heart monitor to keep an eye on her health.
She added: "I was really paranoid about continuing with the tour. There are so many things that could go wrong - somebody could slip, somebody could fall, I could fall from the circus pinwheel I was on. There was no way in hell I was going to jeopardize my baby for my show.
"So I wore this heart monitor that I kept hidden. I didn't want to tell anybody because I didn't want to make the audience uncomfortable, like, 'Pregnant lady onstage! Is she going to be OK?' But I had to announce it to my band and my dancers - because I wanted to make sure they had my back."