diff --git a/lib/fail.js b/lib/fail.js
index 07664e2..1fa49fd 100644
--- a/lib/fail.js
+++ b/lib/fail.js
@@ -41,7 +41,7 @@ module.exports = async (pluginConfig, context) => {
 
   // Override default fail message
   if (configToUse.onFailFunction) {
-    slackMessage = configToUse.onFailFunction(configToUse, context)
+    slackMessage = await Promise.resolve(configToUse.onFailFunction(configToUse, context))
   } else if (configToUse.onFailTemplate) {
     slackMessage = template(configToUse.onFailTemplate, {
       package_name,
diff --git a/lib/success.js b/lib/success.js
index 6f7e7d0..e517d5e 100644
--- a/lib/success.js
+++ b/lib/success.js
@@ -55,7 +55,7 @@ module.exports = async (pluginConfig, context) => {
   let slackMessage = {}
   // Override default success message
   if (configToUse.onSuccessFunction) {
-    slackMessage = configToUse.onSuccessFunction(configToUse, context)
+    slackMessage = await Promise.resolve(configToUse.onSuccessFunction(configToUse, context))
   } else if (configToUse.onSuccessTemplate) {
     slackMessage = template(configToUse.onSuccessTemplate, {
       package_name,