diff --git a/httpie/cli/argparser.py b/httpie/cli/argparser.py
index e243fd3c..64481096 100644
--- a/httpie/cli/argparser.py
+++ b/httpie/cli/argparser.py
@@ -296,6 +296,10 @@ class HTTPieArgumentParser(BaseHTTPieArgumentParser):
                             ' --ignore-stdin is set.'
                         )
                     credentials.prompt_password(url.netloc)
+
+                if (credentials.key and credentials.value):
+                    plugin.raw_auth = credentials.key + ":" + credentials.value
+
                 self.args.auth = plugin.get_auth(
                     username=credentials.key,
                     password=credentials.value,
diff --git a/tests/test_sessions.py b/tests/test_sessions.py
index 5615c08f..58359936 100644
--- a/tests/test_sessions.py
+++ b/tests/test_sessions.py
@@ -15,6 +15,7 @@ from httpie.sessions import Session
 from httpie.utils import get_expired_cookies
 from .test_auth_plugins import basic_auth
 from .utils import HTTP_OK, MockEnvironment, http, mk_config_dir
+from base64 import b64encode
 
 
 class SessionTestBase:
@@ -298,8 +299,6 @@ class TestSession(SessionTestBase):
         assert f'Authorization: {header}' in r2
         plugin_manager.unregister(Plugin)
 
-    @mock.patch('httpie.cli.argtypes.AuthCredentials._getpass',
-                new=lambda self, prompt: 'password')
     def test_auth_plugin_prompt_password_in_session(self, httpbin):
         self.start_session(httpbin)
         session_path = self.config_dir / 'test-session.json'
@@ -308,17 +307,22 @@ class TestSession(SessionTestBase):
             auth_type = 'test-prompted'
 
             def get_auth(self, username=None, password=None):
-                return basic_auth()
+                basic_auth_header = "Basic " + b64encode(self.raw_auth.encode()).strip().decode('latin1')
+                return basic_auth(basic_auth_header)
 
         plugin_manager.register(Plugin)
 
-        r1 = http(
-            '--session', str(session_path),
-            httpbin + '/basic-auth/user/password',
-            '--auth-type',
-            Plugin.auth_type,
-            '--auth', 'user:',
-        )
+        with mock.patch(
+            'httpie.cli.argtypes.AuthCredentials._getpass',
+            new=lambda self, prompt: 'password'
+        ):
+            r1 = http(
+                '--session', str(session_path),
+                httpbin + '/basic-auth/user/password',
+                '--auth-type',
+                Plugin.auth_type,
+                '--auth', 'user',
+            )
 
         r2 = http(
             '--session', str(session_path),
@@ -326,6 +330,13 @@ class TestSession(SessionTestBase):
         )
         assert HTTP_OK in r1
         assert HTTP_OK in r2
+
+        # additional test for issue: https://github.com/httpie/httpie/issues/1098
+        with open(session_path) as session_file:
+            session_file_lines = ''.join(session_file.readlines())
+            assert "\"type\": \"test-prompted\"" in session_file_lines
+            assert "\"raw_auth\": \"user:password\"" in session_file_lines
+
         plugin_manager.unregister(Plugin)
 
     def test_auth_type_stored_in_session_file(self, httpbin):