diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 3a30a63..c9d802d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -278,6 +278,7 @@ jobs:
             type=raw,value=gexp-tag-{{tag}}
             type=raw,value=gexp-baseref-{{base_ref}}
             type=raw,value=gexp-defbranch,enable={{is_default_branch}}
+            type=raw,value=gexp-notdefbranch,enable={{is_not_default_branch}}
 
   json:
     runs-on: ubuntu-latest
diff --git a/README.md b/README.md
index 81220c0..5cbde6e 100644
--- a/README.md
+++ b/README.md
@@ -44,6 +44,7 @@ ___
     * [`{{sha}}`](#sha)
     * [`{{base_ref}}`](#base_ref)
     * [`{{is_default_branch}}`](#is_default_branch)
+    * [`{{is_not_default_branch}}`](#is_not_default_branch)
     * [`{{date '<format>' tz='<timezone>'}}`](#date-format-tztimezone)
     * [`{{commit_date '<format>' tz='<timezone>'}}`](#commit_date-format-tztimezone)
   * [Major version zero](#major-version-zero)
@@ -874,6 +875,11 @@ workflow run. Will be empty for a branch reference:
 Returns `true` if the branch that triggered the workflow run is the default
 one, otherwise `false`.
 
+#### `{{is_not_default_branch}}`
+
+Returns `true` if the branch that triggered the workflow run is not the default
+one, otherwise `false`.
+
 #### `{{date '<format>' tz='<timezone>'}}`
 
 Returns the current date rendered by its [moment format](https://momentjs.com/docs/#/displaying/format/).
diff --git a/__tests__/meta.test.ts b/__tests__/meta.test.ts
index 45d8397..91bfa35 100644
--- a/__tests__/meta.test.ts
+++ b/__tests__/meta.test.ts
@@ -821,6 +821,40 @@ describe('push', () => {
         "org.opencontainers.image.version=mytag-master"
       ],
       undefined
+    ],
+    [
+      'push22',
+      'event_push_dev.env',
+      {
+        images: ['org/app'],
+        tags: [
+          `type=edge,branch=master`,
+          `type=sha,format=long`,
+          `type=raw,value=notdefbranch,enable={{is_not_default_branch}}`
+        ],
+      } as Inputs,
+      {
+        main: 'notdefbranch',
+        partial: [
+          'sha-860c1904a1ce19322e91ac35af1ab07466440c37'
+        ],
+        latest: false
+      } as Version,
+      [
+        "org/app:notdefbranch",
+        "org/app:sha-860c1904a1ce19322e91ac35af1ab07466440c37"
+      ],
+      [
+        "org.opencontainers.image.created=2020-01-10T00:30:00.000Z",
+        "org.opencontainers.image.description=This your first repo!",
+        "org.opencontainers.image.licenses=MIT",
+        "org.opencontainers.image.revision=860c1904a1ce19322e91ac35af1ab07466440c37",
+        "org.opencontainers.image.source=https://github.com/octocat/Hello-World",
+        "org.opencontainers.image.title=Hello-World",
+        "org.opencontainers.image.url=https://github.com/octocat/Hello-World",
+        "org.opencontainers.image.version=notdefbranch"
+      ],
+      undefined
     ]
   ])('given %p with %p event', tagsLabelsTest);
 });
diff --git a/src/meta.ts b/src/meta.ts
index 1f27746..f96d9e7 100644
--- a/src/meta.ts
+++ b/src/meta.ts
@@ -439,6 +439,9 @@ export class Meta {
         }
         return 'false';
       },
+      is_not_default_branch: function () {
+        return this.is_default_branch() === 'false' ? 'true' : 'false';
+      },
       date: function (format, options) {
         const m = moment(currentDate);
         let tz = 'UTC';