diff --git a/emmental/buttons.py b/emmental/buttons.py
index b455477..19cba81 100644
--- a/emmental/buttons.py
+++ b/emmental/buttons.py
@@ -59,6 +59,7 @@ class SplitButton(Gtk.Box):
 
         self.bind_property("icon-name", self._primary, "icon-name")
         self.bind_property("icon-size", self._primary, "icon-size")
+        self._primary.connect("activate", self.__activate)
         self._primary.connect("clicked", self.__clicked)
 
         self.append(self._primary)
@@ -67,14 +68,24 @@ class SplitButton(Gtk.Box):
 
         self.add_css_class("emmental-splitbutton")
 
+    def __activate(self, button: Button) -> None:
+        self.emit("activate-primary")
+
     def __clicked(self, button: Button) -> None:
         self.emit("clicked")
 
+    def activate(self, *args) -> None:
+        self._primary.activate()
+
     @GObject.Property(type=Gtk.Button, flags=GObject.ParamFlags.READABLE)
     def secondary(self) -> Gtk.Button:
         """Get the secondary button attached to the SplitButton."""
         return self._secondary
 
+    @GObject.Signal
+    def activate_primary(self) -> None:
+        """Signal that the primary button has been activated."""
+
     @GObject.Signal
     def clicked(self) -> None:
         """Signal that the primary button has been clicked."""
diff --git a/tests/test_buttons.py b/tests/test_buttons.py
index 6d64572..3904c9b 100644
--- a/tests/test_buttons.py
+++ b/tests/test_buttons.py
@@ -148,6 +148,18 @@ class TestSplitButton(unittest.TestCase):
         self.button._primary.emit("clicked")
         on_click.assert_called_with(self.button)
 
+    def test_activate(self):
+        """Test the activate function."""
+        activate = unittest.mock.Mock()
+        primary = unittest.mock.Mock()
+
+        self.button.connect("activate-primary", primary)
+        self.button._primary.connect("activate", activate)
+
+        self.button.activate()
+        activate.assert_called()
+        primary.assert_called()
+
 
 class TestImageToggle(unittest.TestCase):
     """Test an ImageToggle button."""