diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1ce5d755682a..dae229790967 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -27,6 +27,7 @@
 - `[jest-snapshot]` Downgrade semver to v6 to support node 8 ([#9451](https://github.com/facebook/jest/pull/9451))
 - `[jest-snapshot]` Properly indent new snapshots in the presences of existing ones ([#9523](https://github.com/facebook/jest/pull/9523))
 - `[jest-transform]` Correct sourcemap behavior for transformed and instrumented code ([#9460](https://github.com/facebook/jest/pull/9460))
+- `[jest-transform]` Allow instrumentation of transformed files with weird file extensions ([#9589](https://github.com/facebook/jest/pull/9589))
 - `[pretty-format]` Export `OldPlugin` type ([#9491](https://github.com/facebook/jest/pull/9491))
 
 ### Chore & Maintenance
diff --git a/packages/jest-transform/src/ScriptTransformer.ts b/packages/jest-transform/src/ScriptTransformer.ts
index 8d6a06637be7..18b3b46a07f0 100644
--- a/packages/jest-transform/src/ScriptTransformer.ts
+++ b/packages/jest-transform/src/ScriptTransformer.ts
@@ -213,6 +213,7 @@ export default class ScriptTransformer {
             // files outside `cwd` will not be instrumented
             cwd: this._config.rootDir,
             exclude: [],
+            extension: false,
             // Needed for correct coverage as soon as we start storing a source map of the instrumented code
             inputSourceMap: input.map,
             useInlineSourceMaps: false,