In new court documents, obtained by TMZ.com, Austin Chick reveals Baccarin has told him she's three-and-a-half months pregnant.

He states, "This places the moment of conception right in the first week of June, 2015, the time she was telling me she wanted to work on our marriage and well before we stopped sharing a bed."

Chick filed for divorce later that month (Jun15) and quickly discovered his estranged wife had moved on with her Gotham co-star MCKenzie.

He reveals he returned home to pick up some personal items and found the actor had just had a shower and was playing with Chick's one-year-old son.

In previous legal documents, Morena claimed she and Chick talked about separating in March (15).

She went public with the pregnancy news while fighting for full custody of the couple's son earlier this week (beg21Sep15).

Baccarin told a judge she was concerned that she soon wouldn't be able to fly between her adopted New York and Los Angeles, where Chick lives, to meet the criteria of their existing custody arrangement.

The judge agreed the best course of action would be for the infant to stay in New York with his mother. Chick has been granted visitation.