diff --git a/mithril.js b/mithril.js
index dba767eb..e858251e 100644
--- a/mithril.js
+++ b/mithril.js
@@ -1056,11 +1056,11 @@ var m = (function app(window, undefined) {
 		};
 		prop["catch"] = prop.then.bind(null, null);
 		prop["finally"] = function(callback) {
-			var _callback = function(value) {return m.deferred().resolve(callback(value)).promise;};
+			var _callback = function() {return m.deferred().resolve(callback()).promise;};
 			return prop.then(function(value) {
-				return propify(_callback(value).then(function() {return value;}), initialValue);
+				return propify(_callback().then(function() {return value;}), initialValue);
 			}, function(reason) {
-				return propify(_callback(reason).then(function() {throw new Error(reason);}), initialValue);
+				return propify(_callback().then(function() {throw new Error(reason);}), initialValue);
 			});
 		};
 		return prop;