diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 03820217c8a..aae84540ae8 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -6694,7 +6694,6 @@ export interface Signature {
     declaration?: SignatureDeclaration | JSDocSignature; // Originating declaration
     typeParameters?: readonly TypeParameter[];   // Type parameters (undefined if non-generic)
     parameters: readonly Symbol[];               // Parameters
-    /** @internal */
     thisParameter?: Symbol;             // symbol of this-type parameter
     /** @internal */
     // See comment in `instantiateSignature` for why these are set lazily.
diff --git a/tests/baselines/reference/api/typescript.d.ts b/tests/baselines/reference/api/typescript.d.ts
index 98f1b330003..dcacb96447a 100644
--- a/tests/baselines/reference/api/typescript.d.ts
+++ b/tests/baselines/reference/api/typescript.d.ts
@@ -7313,6 +7313,7 @@ declare namespace ts {
         declaration?: SignatureDeclaration | JSDocSignature;
         typeParameters?: readonly TypeParameter[];
         parameters: readonly Symbol[];
+        thisParameter?: Symbol;
     }
     interface Signature {
         getDeclaration(): SignatureDeclaration;