diff --git a/packages/svelte/tests/runtime-runes/samples/class-state-constructor-predeclared-field/_config.js b/packages/svelte/tests/runtime-runes/samples/class-state-constructor-predeclared-field/_config.js
new file mode 100644
index 0000000000..02cf36d900
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/class-state-constructor-predeclared-field/_config.js
@@ -0,0 +1,20 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	html: `<button>0</button>`,
+
+	test({ assert, target }) {
+		const btn = target.querySelector('button');
+
+		flushSync(() => {
+			btn?.click();
+		});
+		assert.htmlEqual(target.innerHTML, `<button>1</button>`);
+
+		flushSync(() => {
+			btn?.click();
+		});
+		assert.htmlEqual(target.innerHTML, `<button>2</button>`);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/class-state-constructor-predeclared-field/main.svelte b/packages/svelte/tests/runtime-runes/samples/class-state-constructor-predeclared-field/main.svelte
new file mode 100644
index 0000000000..5dbbb10afd
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/class-state-constructor-predeclared-field/main.svelte
@@ -0,0 +1,12 @@
+<script>
+	class Counter {
+		count;
+
+		constructor(count) {
+			this.count = $state(count);
+		}
+	}
+	const counter = new Counter(0);
+</script>
+
+<button onclick={() => counter.count++}>{counter.count}</button>