The discovery rule applies to claims of legal malpractice. See Murphy, 964 S.W.2d at 270; Willis v. Maverick, 760 S.W.2d 642, 646 (Tex. 1988). Thus, the statute of limitations for legal malpractice actions does not begin to run until the claimant discovers or should have discovered through the exercise of reasonable care and diligence the facts establishing the elements of his cause of action. Willis, 760 S.W.2d at 646. When a defendant in a legal malpractice action moves for summary judgment based on the defense of limitations, it has the burden of: (1) showing when the cause of action accrued; (2) negating the discovery rule by proving as a matter of law that there is no genuine issue of fact about when the plaintiff discovered or in the exercise of reasonable diligence should have discovered the facts establishing the cause of action. Woods v. Mercer, 769 S.W.2d 515, 518 n.2 (Tex. 1988); Rea v. Cofer, 879 S.W.2d 224, 228 (Tex. App.-Houston [14th Dist.] 1994, no writ).