diff --git a/lib/dynamic.js b/lib/dynamic.js
index b375bb3c..0ac0eef0 100644
--- a/lib/dynamic.js
+++ b/lib/dynamic.js
@@ -64,13 +64,7 @@ export class SameLoopPromise {
   constructor (cb) {
     this.onResultCallbacks = []
     this.onErrorCallbacks = []
-
-    if (cb) {
-      cb(
-        (result) => this.setResult(result),
-        (error) => this.setError(error)
-      )
-    }
+    this.cb = cb
   }
 
   setResult (result) {
@@ -88,6 +82,7 @@ export class SameLoopPromise {
   }
 
   then (onResult, onError) {
+    this.runIfNeeded()
     const promise = new SameLoopPromise()
 
     const handleError = () => {
@@ -119,6 +114,7 @@ export class SameLoopPromise {
   }
 
   catch (onError) {
+    this.runIfNeeded()
     const promise = new SameLoopPromise()
 
     const handleError = () => {
@@ -144,4 +140,15 @@ export class SameLoopPromise {
 
     return promise
   }
+
+  runIfNeeded () {
+    if (!this.cb) return
+    if (this.ran) return
+
+    this.ran = true
+    this.cb(
+      (result) => this.setResult(result),
+      (error) => this.setError(error)
+    )
+  }
 }