diff --git a/tfworker/commands/terraform.py b/tfworker/commands/terraform.py
index ebbd222..4d5f268 100644
--- a/tfworker/commands/terraform.py
+++ b/tfworker/commands/terraform.py
@@ -415,6 +415,7 @@ def _run(
                     self._terraform_bin,
                     debug=debug,
                     b64_encode=self._b64_encode,
+                    extra_vars=definition.template_vars,
                 )
         except HookError as e:
             click.secho(
@@ -487,6 +488,7 @@ def _run(
                     self._terraform_bin,
                     debug=debug,
                     b64_encode=self._b64_encode,
+                    extra_vars=definition.template_vars,
                 )
         except HookError as e:
             click.secho(
@@ -504,6 +506,7 @@ def hook_exec(
         terraform_path,
         debug=False,
         b64_encode=False,
+        extra_vars={},
     ):
         """
         hook_exec executes a hook script.
@@ -559,9 +562,7 @@ def hook_exec(
 
                     if state_value is not None:
                         if b64_encode:
-                            state_value = base64.b64encode(
-                                state_value.encode("utf-8")
-                            ).decode()
+                            state_value = base64.b64encode(state_value.encode("utf-8"))
                         local_env[f"TF_REMOTE_{state}_{item}".upper()] = state_value
 
         # populate environment with terraform variables
@@ -578,7 +579,7 @@ def hook_exec(
                         tf_var[1] = tf_var[1].replace(k, v)
 
                     if b64_encode:
-                        tf_var[1] = base64.b64encode(tf_var[1].encode("utf-8")).decode()
+                        tf_var[1] = base64.b64encode(tf_var[1].encode("utf-8"))
 
                     local_env[f"TF_VAR_{tf_var[0].upper()}"] = tf_var[1]
         else:
@@ -587,6 +588,11 @@ def hook_exec(
                 fg="red",
             )
 
+        for k, v in extra_vars.items():
+            if b64_encode:
+                v = base64.b64encode(v.encode("utf-8"))
+            local_env[f"TF_EXTRA_{k.upper()}"] = v
+
         # execute the hook
         (exit_code, stdout, stderr) = pipe_exec(
             f"{hook_script} {phase} {command}",
diff --git a/tfworker/definitions.py b/tfworker/definitions.py
index e278520..aaa7760 100644
--- a/tfworker/definitions.py
+++ b/tfworker/definitions.py
@@ -115,6 +115,10 @@ def provider_names(self):
     def plan_file(self):
         return self._plan_file
 
+    @property
+    def template_vars(self):
+        return self._template_vars
+
     @plan_file.setter
     def plan_file(self, value: Path):
         if type(value) not in [PosixPath, WindowsPath, Path]: