TMZ has learned Oksana Grigorieva will take the oath -- swearing to tell the truth tomorrow when she is deposed in the child custody dispute with Mel Gibson.
Sources tell us Oksana and her attorneys will meet with Mel's attorneys.
This could be tricky for Oksana because although the primary focus will be custody of Lucia, the topic of the tapes will most likely come up -- the recording and sale of them. Oksana could invoke her Fifth Amendment rights and refuse to talk about that subject.
Either way, tomorrow's events will be critical in this case. Check in with TMZ for all the updates.