diff --git a/resources/function_help/$map b/resources/function_help/$map
new file mode 100644
index 00000000000..2df33a72e25
--- /dev/null
+++ b/resources/function_help/$map
@@ -0,0 +1,16 @@
+<h3>$map function</h3>
+Returns the id of the current map item if the map is being drawn in a composition, or "canvas" if the map is being
+drawn within the main QGIS window.
+
+<h4>Syntax</h4>
+<pre>$map</pre>
+
+<h4>Arguments</h4>
+None
+
+<h4>Example</h4>
+<!-- Show example of function.-->
+<pre>$map &rarr; "overview_map" (within a composer item)<br />
+$map &rarr; "canvas" (within the main QGIS main canvas)</pre>
+
+
diff --git a/src/core/composer/qgscomposermap.cpp b/src/core/composer/qgscomposermap.cpp
index 2119358b502..c831937aa9d 100644
--- a/src/core/composer/qgscomposermap.cpp
+++ b/src/core/composer/qgscomposermap.cpp
@@ -28,6 +28,7 @@
 #include "qgsscalecalculator.h"
 #include "qgsvectorlayer.h"
 #include "qgspallabeling.h"
+#include "qgsexpression.h"
 
 #include "qgslabel.h"
 #include "qgslabelattributes.h"
@@ -226,6 +227,9 @@ void QgsComposerMap::draw( QPainter *painter, const QgsRectangle& extent, const
   bool bkLayerCaching = s.value( "/qgis/enable_render_caching", false ).toBool();
   s.setValue( "/qgis/enable_render_caching", false );
 
+  //update $map variable. Use QgsComposerItem's id since that is user-definable
+  QgsExpression::setSpecialColumn( "$map", QgsComposerItem::id() );
+
   if ( forceWidthScale ) //force wysiwyg line widths / marker sizes
   {
     theMapRenderer.render( painter, forceWidthScale );
diff --git a/src/gui/qgsmapcanvas.cpp b/src/gui/qgsmapcanvas.cpp
index e475af62105..08ed4b3ca2b 100644
--- a/src/gui/qgsmapcanvas.cpp
+++ b/src/gui/qgsmapcanvas.cpp
@@ -417,6 +417,9 @@ void QgsMapCanvas::refresh()
 
   mDrawing = true;
 
+  //update $map variable to canvas
+  QgsExpression::setSpecialColumn( "$map", tr( "canvas" ) );
+
   if ( mRenderFlag && !mFrozen )
   {
     clear();