diff --git a/resources/js/ext.uls.interface.js b/resources/js/ext.uls.interface.js
index 88b890b6..50569207 100644
--- a/resources/js/ext.uls.interface.js
+++ b/resources/js/ext.uls.interface.js
@@ -163,6 +163,27 @@
 		} );
 	}
 
+	/**
+	 * Gets the name of the previously active language
+	 * @param {string} code Language code of previously selected language.
+	 * @return {jQuery.Promise}
+	 */
+	function getUndoAutonym( code ) {
+		var
+			deferred = $.Deferred(),
+			autonym = $.cookie( mw.uls.previousLanguageAutonymCookie );
+
+		if ( autonym ) {
+			deferred.resolve( autonym );
+		} else {
+			mw.loader.using( 'jquery.uls.data', function () {
+				deferred.resolve( $.uls.data.getAutonym( code ) );
+			} );
+		}
+
+		return deferred.promise();
+	}
+
 	/**
 	 * The tooltip to be shown when language changed using ULS.
 	 * It also allows to undo the language selection.
@@ -171,7 +192,6 @@
 		var ulsPosition = mw.config.get( 'wgULSPosition' ),
 			currentLang = mw.config.get( 'wgUserLanguage' ),
 			previousLang,
-			previousLanguageAutonym,
 			$ulsTrigger,
 			anonMode,
 			rtlPage = $( 'body' ).hasClass( 'rtl' ),
@@ -203,35 +223,34 @@
 			return;
 		}
 
-		previousLanguageAutonym = $.cookie( mw.uls.previousLanguageAutonymCookie ) ||
-			previousLang;
+		getUndoAutonym( previousLang ).done( function( autonym ) {
+			// Attach a tipsy tooltip to the trigger
+			$ulsTrigger.tipsy( {
+				gravity: tipsyGravity[ulsPosition],
+				delayOut: 3000,
+				html: true,
+				fade: true,
+				trigger: 'manual',
+				title: function () {
+					var link;
 
-		// Attach a tipsy tooltip to the trigger
-		$ulsTrigger.tipsy( {
-			gravity: tipsyGravity[ulsPosition],
-			delayOut: 3000,
-			html: true,
-			fade: true,
-			trigger: 'manual',
-			title: function () {
-				var link;
+					link = $( '<a>' ).text( autonym )
+						.attr( {
+							href: '#',
+							'class': 'uls-prevlang-link',
+							lang: previousLang,
+							// We could get dir from uls.data,
+							// but we are trying to avoid loading it
+							// and 'auto' is safe enough in this context
+							dir: 'auto'
+						} );
 
-				link = $( '<a>' ).text( previousLanguageAutonym )
-					.attr( {
-						href: '#',
-						'class': 'uls-prevlang-link',
-						lang: previousLang,
-						// We could get dir from uls.data,
-						// but we are trying to avoid loading it
-						// and 'auto' is safe enough in this context
-						dir: 'auto'
-					} );
+					// Get the html of the link by wrapping it in div first
+					link = $( '<div>' ).html( link ).html();
 
-				// Get the html of the link by wrapping it in div first
-				link = $( '<div>' ).html( link ).html();
-
-				return mw.message( 'ext-uls-undo-language-tooltip-text', '$1' ).escaped().replace( '$1', link );
-			}
+					return mw.message( 'ext-uls-undo-language-tooltip-text', '$1' ).escaped().replace( '$1', link );
+				}
+			} );
 		} );
 
 		// Now that we set the previous languages,