Article 127 of Indian Constitution

Appointment of ad hoc Judges.—(1) If at any time there should not be a quorum of the Judges of the Supreme Court available to hold or continue any session of the Court, [the National Judicial Appointments Commission on a reference made to it by the Chief Justice of India, may with the previous consent of the President] and after consultation with the Chief Justice of the High Court concerned, request in writing the attendance at the sittings of the Court, as an ad hoc Judge, for such period as may be necessary, of a Judge of a High Court duly qualified for appointment as a Judge of the Supreme Court to be designated by the Chief Justice of India.

(2) It shall be the duty of the Judge who has been so designated, in priority to other duties of his office, to attend the sittings of the Supreme Court at the time and for the period for which his attendance is required, and while so attending he shall have all the jurisdiction, powers and privileges, and shall discharge the duties, of a Judge of the Supreme Court.