diff --git a/ArmPkg/Library/ArmLib/AArch64/AArch64ArchTimerSupport.S b/ArmPkg/Library/ArmLib/AArch64/AArch64ArchTimerSupport.S
index 1ac01086aa..3944d8bcb4 100644
--- a/ArmPkg/Library/ArmLib/AArch64/AArch64ArchTimerSupport.S
+++ b/ArmPkg/Library/ArmLib/AArch64/AArch64ArchTimerSupport.S
@@ -58,7 +58,7 @@ ASM_PFX(ArmReadCntkCtl):
 
 
 ASM_PFX(ArmWriteCntkCtl):
-  mrs   x0, cntkctl_el1          // Write to CNTK_CTL (Timer PL1 Control Register)
+  msr   cntkctl_el1, x0          // Write to CNTK_CTL (Timer PL1 Control Register)
   ret