The devastated couple released a statement on Thursday announcing their son Harrison was stillborn.
"It is with great sadness that we need to share some news with you. Our baby boy Harrison was delivered stillborn on Thursday 7 August 2014.
"We appreciate your love and support as we mourn the loss of our precious son.
"We understand we have lived some of our lives in the public eye. But we respectfully ask for privacy at this difficult and extremely painful time so we can grieve and heal."
The Home and Away star and her partner welcomed their first child, son Johnas, in 2012 after an enduring process of IVF.
Earlier this year Nicodemou, 37, confirmed she had fallen pregnant for a second time naturally.
In a March interview to announce the new pregnancy, the actress who plays Leah on the TV soap, said it had come as a "surprise".
"For it to happen so quickly after we struggled for so long last time is a really nice surprise and we feel really, really lucky," she said.