In the current Trump–BBC defamation case, Trump is the plaintiff (he sued the BBC). Parties who file lawsuits are generally required to participate in discovery, including depositions. A federal magistrate judge has ordered him to sit for the deposition by December 11, 2026, after earlier delays; non-compliance risks sanctions up to dismissal of his suit. Depositions are typically taken out of court (in a lawyer’s office or similar setting, recorded by a court reporter), not as live “standing in court” trial testimony, though the transcript or video can be used in later proceedings.