Isla and Sacha: It’s a boy!

Isla Fisher and Sacha Baron Cohen are the proud parents of a one-month-old baby boy.

While last week it was revealed that the couple had welcomed their third child into the world, no word was given as to the baby’s gender or exactly when he or she was born.

However, TMZ has now obtained a copy of the infant’s birth certificate, which was filed with the LA County Department of Public Health, stating that the child – a son named Montgomery Moses Brian Baron Cohen – was born on March 17.

The birth certificate also reveals that Isla gave birth at celebrity-favoured Cedars-Sinai Medical Center in Los Angeles.

Montgomery is the first son for the couple, who are already parents to daughters Olive, seven, and Elula, four.

It’s not known if the 39-year-old Australian actress and her 43-year-old British actor-comedian husband of five years found out the baby’s sex prior to his birth. However, it was previously reported that Isla believed she was expecting a boy due to how differently her body was reacting third time around.

"Isla's exhausted. Sacha helps, but she's been finding this pregnancy her toughest yet because her daughters are so active," a source told British magazine Closer back in January, adding, "Luckily, she hasn't had morning sickness this time and feels that could be a sign she's having a boy!"

The heavily pregnant star was last seen in public on March 13, running errands in Los Angeles.

She then sparked speculation she had secretly given birth as she attended a private party at Lucy's El Adobe in LA on April 9 minus her baby bump.

Us Weekly exclusively confirmed on April 10 that she had indeed welcomed the couple's third child on an unspecified date.