A lawyer represented a client in a case involving a contract dispute. The lawyer was successful in showing a breach of contract by the defendant and asserted a claim for attorneys’ fees under the contract. The defendant did not dispute that the plaintiff was entitled to attorneys’ fees, but argued that the lawyer overcharged his client since the work performed was not worth the amount charged. At the hearing on the motion for attorneys’ fees, the defendant’s attorney called the plaintiff’s lawyer as a witness. Can the lawyer testify in a case in which he is representing a party?