Holly Madison is expecting a baby boy.

Meanwhile, the 'Down the Rabbit Hole: Curious Adventures and Cautionary Tales of a Former Playboy Bunny' author previously predicted the gender of her child in an interview back in January, where she confirmed she was three months into her pregnancy.

She said: "I'm so excited. This time I know what to expect a little bit more. [That] makes it even more enjoyable! I'm kind of feeling the boy vibe. We'll see how psychic I am!

"Rainbow was the first person my husband and I told. She's rooting for a girl. I think she's going to be a good big sister. She's very caring and she loves playing with her baby dolls and taking care of the pets."

And being a former Playboy Playmate, Holly is known for her enviable figure, although she insists she's not too worried about gaining weight during her pregnancy.

She added: "I gained a healthy amount last time. And I lost it pretty easily. I'm not really putting the pressure on myself. Worst case scenario, I'll just get lipo!"