Hollywood actress and new mother Olivia Wilde has refused to sugar-coat the reality of giving birth and motherhood, exposing the truth about post-pregnancy life in a hilarious new interview.

The 31-year-old gave birth to son Otis Alexander, her first child with her fiance, actor Jason Sudeikis, on 20 April, 2014, and while she has embraced her new life as a mother, the Rush actress admits it has been a struggle to lose the baby weight.

In a candid interview with Shape magazine, Wilde said: "For a couple of weeks after you pop that sucker out, you are the walking wounded. First of all, you haven't seen your vagina in months, even though it's all her fault you're in this situation.

"Now that you can finally confirm that she is, in fact, still there, she isn't the gal you remember, and would rather you back off and give her some space (and an ice diaper) for the time being, thank you very much."

After describing her stomach post-birth as a "partially deflated pool toy", Wilde continues: "Breast-feeding helps, in the most intense way. You feel your uterus contracting while the baby nurses. Your belly starts to go down. Your thighs become slightly less thunderous.

"Finally, you are ready to change out of sweatpants, but when you manage to button your jeans (thank you, stretchy denim), the button clasp gets swallowed up and lost in your gelatinous Stay Puft Marshmallow Man belly."

Detailing her new workout regime, Wilde admits that she would rather spend time bonding with her first-born. The actress told the magazine: "I knew the exercise was a crucial element of 'me time', but it felt like leaving a karaoke bar to go take a physics exam.

"If I wasn't at work, I just wanted to stay home and party with my little man - and by 'party', I mean, of course, endless rounds of the Itsy Bitsy Spider. Also, I like beer. And pizza."

Thanks for the honesty!

Wilde got engaged to Horrible Bosses actor Sudeikis in January 2013 and they have been dating since 2011.