Tex. Government Code § 24.004: SPECIAL JUDGE BY AGREEMENT OF PARTIES.

If the parties agree on a special judge for the trial of a particular case, the clerk shall enter in the minutes of the court, as a part of the proceedings in the case, a record showing:

(1) that the judge of the court is disqualified to try the case;

(2) the name of the special judge and that the parties agreed on the selection of that judge for the trial of the case; and

(3) that the oath prescribed by law was administered to the special judge.

Acts 1985, 69th Leg., ch. 480, Sec. 1, eff. Sept. 1, 1985.