diff --git a/gajim/common/config.py b/gajim/common/config.py
index ef03d4100..40f0e2a3d 100644
--- a/gajim/common/config.py
+++ b/gajim/common/config.py
@@ -50,7 +50,7 @@ class Option(IntEnum):
 opt_int = [ 'integer', 0 ]
 opt_str = [ 'string', 0 ]
 opt_bool = [ 'boolean', 0 ]
-opt_color = [ 'color', '^(#[0-9a-fA-F]{6})|()$' ]
+opt_color = [ 'color', '^(#[0-9a-fA-F]{6})|()|rgb\(\d+,\d+,\d+\)|rgba\(\d+,\d+,\d+,[01]\.?\d*\)$' ]
 opt_one_window_types = ['never', 'always', 'always_with_roster', 'peracct', 'pertype']
 opt_show_roster_on_startup = ['always', 'never', 'last_state']
 opt_treat_incoming_messages = ['', 'chat', 'normal']
diff --git a/gajim/config.py b/gajim/config.py
index a51851461..61ad624fd 100644
--- a/gajim/config.py
+++ b/gajim/config.py
@@ -849,7 +849,7 @@ class PreferencesWindow:
 
     def on_preference_widget_color_set(self, widget, text):
         color = widget.get_color()
-        color_string = gtkgui_helpers.make_color_string(color)
+        color_string = color.to_string()
         app.config.set(text, color_string)
         self.update_text_tags()
 
@@ -946,8 +946,8 @@ class PreferencesWindow:
         Set color value in prefs and update the UI
         """
         if state:
-            color = self.xml.get_object(widget_name).get_color()
-            color_string = gtkgui_helpers.make_color_string(color)
+            color = self.xml.get_object(widget_name).get_rgba()
+            color_string = color.to_string()
         else:
             color_string = ''
         app.config.set(option, color_string)
diff --git a/gajim/gajim_themes_window.py b/gajim/gajim_themes_window.py
index 040edaf2c..0ea5490a8 100644
--- a/gajim/gajim_themes_window.py
+++ b/gajim/gajim_themes_window.py
@@ -285,8 +285,8 @@ class GajimThemesWindow:
         Set color value in prefs and update the UI
         """
         if state:
-            color = widget.get_color()
-            color_string = gtkgui_helpers.make_color_string(color)
+            color = widget.get_rgba()
+            color_string = color.to_string()
         else:
             color_string = ''
         begin_option = ''
diff --git a/gajim/gtkgui_helpers.py b/gajim/gtkgui_helpers.py
index 47f0bad86..142895ce6 100644
--- a/gajim/gtkgui_helpers.py
+++ b/gajim/gtkgui_helpers.py
@@ -541,19 +541,6 @@ def make_gtk_month_python_month(month):
 def make_python_month_gtk_month(month):
     return month - 1
 
-def make_color_string(color):
-    """
-    Create #aabbcc color string from gtk color
-    """
-    col = '#'
-    for i in ('red', 'green', 'blue'):
-        h = hex(int(getattr(color, i) / (16*16)))
-        h = h.split('x')[1]
-        if len(h) == 1:
-            h = '0' + h
-        col += h
-    return col
-
 def make_pixbuf_grayscale(pixbuf):
     pixbuf2 = pixbuf.copy()
     pixbuf.saturate_and_pixelate(pixbuf2, 0.0, False)