Tex. Civ. Prac. & Rem. Code § 27.005
(b) Except as provided by Subsection (c), on the motion of a party under Section 27.003, a court shall dismiss a legal action against the moving party if the moving party shows by a preponderance of the evidence that the legal action is based on, relates to, or is in response to the party's exercise of:
Added by Acts 2011, 82nd Leg., R.S., Ch. 341 (H.B. 2973), Sec. 2, eff. June 17, 2011.