The invention relates to an actuator (4) for controlling a horizontal stabilizer (3) of an aircraft, including: a primary channel including a screw (6) and a primary nut (7), the primary nut (7) being suitable for engaging with the screw (6), such that a rotation of the screw (6) relative to the primary nut (7) about a rotation axis (X) causes the primary nut (7) to translate relative to the screw (6) along the axis (X), such as to move the horizontal stabilizer (3); a secondary channel including a secondary part (25, 28), and a housing (23, 26), the secondary part (25, 28) being mounted in the housing (23, 26) with play between the secondary part and the housing, in which the secondary channel also includes a play take-up device (27), configured to, in the event of a breakdown of the primary channel causing the secondary part (25, 28) to move relative to the housing, eliminate the play between the secondary part (25, 28) and the housing (23, 26) such as to keep the secondary part (25, 28) in contact with the housing (23, 26).