tried to keep her pregnancy a secret from the cast and crew of her new movie Eastern Promises
, but couldn't hide the good news from the director's sister, who was the film's costume designer.
The actress discovered she was expecting boyfriend Liev Schreiber
's child two weeks into the shoot and her happiness quickly turned into a struggle to fight tiredness and nausea - so as not to reveal her state.
Watts felt sure she was doing OK until director David Cronenberg
's sister discovered she wasn't fitting into her costumes.
star says, "We were shooting mostly nights. It was tough. I was not feeling my best. (But) in the first 12 weeks of pregnancy, you like to keep it a secret, so I was tired and not feeling well and not getting enough sympathy."
Director Cronenberg adds, "My sister knew before anyone else because she's the costume designer. She said that Naomi's not fitting into her clothes anymore."
Baby Alexander Pete was born in Los Angeles on July 26.
-Naomi Watts Pictures
(This news article provided by World Entertainment News Network)