diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 7e14ff22dede6..2078ef0e6d252 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -6716,7 +6716,6 @@ 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/tsserverlibrary.d.ts b/tests/baselines/reference/api/tsserverlibrary.d.ts
index 760a948efc21a..a320a3933600c 100644
--- a/tests/baselines/reference/api/tsserverlibrary.d.ts
+++ b/tests/baselines/reference/api/tsserverlibrary.d.ts
@@ -6901,6 +6901,7 @@ declare namespace ts {
         declaration?: SignatureDeclaration | JSDocSignature;
         typeParameters?: readonly TypeParameter[];
         parameters: readonly Symbol[];
+        thisParameter?: Symbol;
     }
     interface Signature {
         getDeclaration(): SignatureDeclaration;
diff --git a/tests/baselines/reference/api/typescript.d.ts b/tests/baselines/reference/api/typescript.d.ts
index 85d2a5b10a201..e355a257a3992 100644
--- a/tests/baselines/reference/api/typescript.d.ts
+++ b/tests/baselines/reference/api/typescript.d.ts
@@ -2958,6 +2958,7 @@ declare namespace ts {
         declaration?: SignatureDeclaration | JSDocSignature;
         typeParameters?: readonly TypeParameter[];
         parameters: readonly Symbol[];
+        thisParameter?: Symbol;
     }
     interface Signature {
         getDeclaration(): SignatureDeclaration;