diff --git a/packages/babel-plugin-transform-typescript/src/index.ts b/packages/babel-plugin-transform-typescript/src/index.ts
index 9ffd38dd926a..6e120675f064 100644
--- a/packages/babel-plugin-transform-typescript/src/index.ts
+++ b/packages/babel-plugin-transform-typescript/src/index.ts
@@ -124,7 +124,11 @@ export default declare((api, opts: Options) => {
         if (!process.env.BABEL_8_BREAKING) {
           // keep the definitely assigned fields only when `allowDeclareFields` (equivalent of
           // Typescript's `useDefineForClassFields`) is true
-          if (!allowDeclareFields && !node.decorators) {
+          if (
+            !allowDeclareFields &&
+            !node.decorators &&
+            !t.isClassPrivateProperty(node)
+          ) {
             path.remove();
           }
         }
diff --git a/packages/babel-plugin-transform-typescript/test/fixtures/class/uninitialized-definite-babel-7/input.ts b/packages/babel-plugin-transform-typescript/test/fixtures/class/uninitialized-definite-babel-7/input.ts
index 9716f73fa6a5..4aa546ac422d 100644
--- a/packages/babel-plugin-transform-typescript/test/fixtures/class/uninitialized-definite-babel-7/input.ts
+++ b/packages/babel-plugin-transform-typescript/test/fixtures/class/uninitialized-definite-babel-7/input.ts
@@ -1,3 +1,5 @@
 class A {
   x!;
+
+  #y!;
 }
diff --git a/packages/babel-plugin-transform-typescript/test/fixtures/class/uninitialized-definite-babel-7/output.js b/packages/babel-plugin-transform-typescript/test/fixtures/class/uninitialized-definite-babel-7/output.js
index eebf5c5c33db..60badd3faf37 100644
--- a/packages/babel-plugin-transform-typescript/test/fixtures/class/uninitialized-definite-babel-7/output.js
+++ b/packages/babel-plugin-transform-typescript/test/fixtures/class/uninitialized-definite-babel-7/output.js
@@ -1,3 +1,4 @@
 class A {
   x;
+  #y;
 }
diff --git a/packages/babel-plugin-transform-typescript/test/fixtures/class/uninitialized-definite-with-declare-disabled-babel-7/input.ts b/packages/babel-plugin-transform-typescript/test/fixtures/class/uninitialized-definite-with-declare-disabled-babel-7/input.ts
index 9716f73fa6a5..4aa546ac422d 100644
--- a/packages/babel-plugin-transform-typescript/test/fixtures/class/uninitialized-definite-with-declare-disabled-babel-7/input.ts
+++ b/packages/babel-plugin-transform-typescript/test/fixtures/class/uninitialized-definite-with-declare-disabled-babel-7/input.ts
@@ -1,3 +1,5 @@
 class A {
   x!;
+
+  #y!;
 }
diff --git a/packages/babel-plugin-transform-typescript/test/fixtures/class/uninitialized-definite-with-declare-disabled-babel-7/output.js b/packages/babel-plugin-transform-typescript/test/fixtures/class/uninitialized-definite-with-declare-disabled-babel-7/output.js
index a869c2849526..e2acdc9c7dee 100644
--- a/packages/babel-plugin-transform-typescript/test/fixtures/class/uninitialized-definite-with-declare-disabled-babel-7/output.js
+++ b/packages/babel-plugin-transform-typescript/test/fixtures/class/uninitialized-definite-with-declare-disabled-babel-7/output.js
@@ -1 +1,3 @@
-class A {}
+class A {
+  #y;
+}