EXCLUSIVE

Celeb lawyer Steve Kolodny tells TMZ a report in Us Weekly is bogus ... a report claiming Halle and fiance Olivier have hashed out a prenatal agreement in which he agreed to pay her child support if they break up. Kolodny says not only is there no deal, there hasn't been a discussion or even a whisper about one.
TMZ broke the story ... Halle is a little more than 3 months pregnant with her second child -- predestined to be a very good looking boy.
What's more ... Kolodny says any agreement not ratified by a judge -- where one parent gives up the right to an unborn child would be unenforceable.