diff --git a/dist/index.js b/dist/index.js
index 8967d20..223270a 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -161,13 +161,13 @@ function slugify(str) {
 // https://help.github.com/en/actions/automating-your-workflow-with-github-actions/using-environment-variables#default-environment-variables
 try {
     splitted_github_repository = process.env.GITHUB_REPOSITORY.split('/'); // octocat/Hello-World
-    process.env['GITHUB_REPO_OWNER'] = slugify(splitted_github_repository[0]);
+    core.exportVariable('GITHUB_REPO_OWNER', slugify(splitted_github_repository[0]));
     core.info(`Set GITHUB_REPO_OWNER=${process.env.GITHUB_REPO_OWNER}`);
-    process.env['GITHUB_REPO_NAME'] = slugify(splitted_github_repository[1]);
+    core.exportVariable('GITHUB_REPO_NAME', slugify(splitted_github_repository[1]));
     core.info(`Set GITHUB_REPO_NAME=${process.env.GITHUB_REPO_NAME}`);
 
     splitted_github_ref = process.env.GITHUB_REF.split('/'); // refs/heads/feature-branch-1
-    process.env['GITHUB_BRANCH_NAME'] = slugify(splitted_github_ref[2]);
+    core.exportVariable('GITHUB_BRANCH_NAME', slugify(splitted_github_ref[2]));
     core.info(`Set GITHUB_BRANCH_NAME=${process.env.GITHUB_BRANCH_NAME}`);
 } catch (error) {
     core.setFailed(error.message);
diff --git a/index.js b/index.js
index 98220d1..51d46d4 100644
--- a/index.js
+++ b/index.js
@@ -14,13 +14,13 @@ function slugify(str) {
 // https://help.github.com/en/actions/automating-your-workflow-with-github-actions/using-environment-variables#default-environment-variables
 try {
     splitted_github_repository = process.env.GITHUB_REPOSITORY.split('/'); // octocat/Hello-World
-    process.env['GITHUB_REPO_OWNER'] = slugify(splitted_github_repository[0]);
+    core.exportVariable('GITHUB_REPO_OWNER', slugify(splitted_github_repository[0]));
     core.info(`Set GITHUB_REPO_OWNER=${process.env.GITHUB_REPO_OWNER}`);
-    process.env['GITHUB_REPO_NAME'] = slugify(splitted_github_repository[1]);
+    core.exportVariable('GITHUB_REPO_NAME', slugify(splitted_github_repository[1]));
     core.info(`Set GITHUB_REPO_NAME=${process.env.GITHUB_REPO_NAME}`);
 
     splitted_github_ref = process.env.GITHUB_REF.split('/'); // refs/heads/feature-branch-1
-    process.env['GITHUB_BRANCH_NAME'] = slugify(splitted_github_ref[2]);
+    core.exportVariable('GITHUB_BRANCH_NAME', slugify(splitted_github_ref[2]));
     core.info(`Set GITHUB_BRANCH_NAME=${process.env.GITHUB_BRANCH_NAME}`);
 } catch (error) {
     core.setFailed(error.message);