Amanda Bynes will be in court Friday --TMZ has learned -- and we're told she will mount a ferocious fight for her freedom.

Sources involved in the case tell TMZ ... Amanda will be transported from the psychiatric hospital -- where she's been staying against her will for the last 2 weeks -- to a courthouse where her parents will be asking a judge for a temporary conservatorship.

We're told Amanda will be transported by a hospital vehicle and accompanied by her lawyer. The only snag would be if Amanda goes off the rails before the hearing.

Sources tell us Amanda will be speaking with the judge -- possibly in chambers -- so he can get a read on her mental competency.

If the parents prevail, the temporary conservatorship will last until Sept. 30, when a full-blown conservatorship hearing will take place. If the parents get their way, Amanda will go back to the psych ward for further treatment.

If Amanda prevails, she will walk out of the courthouse a free woman.

We'll be there, so stay tuned.