The Australian model - who married long-term boyfriend Orlando Bloom in a secret ceremony earlier this month - is said to have told close friends that she is "thrilled" to be expecting her first child.
A source said: "She`s definitely pregnant... Miranda`s thrilled. She`s telling all her friends, mostly other models, about it."
The Victoria-s Secret model and her 33-year-old spouse are not planning to make an official announcement about their impending new arrival, but the 27-year-old beauty-s pal insists it will be hard to conceal her news.
The source added to US Weekly magazine: "She poses in lingerie. It will be obvious soon enough."
Miranda - who is believed to be three months pregnant - has previously spoken about her desire to start a family with the -Pirates of the Caribbean- star, who she has been in a relationship with for three years.
She said recently: "I have always been very open about wanting to be a mother one day. And I`ve always thought Orlando would be a great dad!"
The couple have kept all details of their recent nuptials under wraps, but it is believed they tied the knot in an intimate ceremony in the Caribbean.