diff --git a/components/style/gecko/generated/bindings.rs b/components/style/gecko/generated/bindings.rs
index 3f1fe721076..f21f9005867 100644
--- a/components/style/gecko/generated/bindings.rs
+++ b/components/style/gecko/generated/bindings.rs
@@ -2618,6 +2618,10 @@ extern "C" {
                                                RawServoAnimationValueBorrowed)
      -> f32;
 }
+extern "C" {
+    pub fn Servo_AnimationValue_Opacity(arg1: f32)
+     -> RawServoAnimationValueStrong;
+}
 extern "C" {
     pub fn Servo_AnimationValue_GetTransform(value:
                                                  RawServoAnimationValueBorrowed,
diff --git a/ports/geckolib/glue.rs b/ports/geckolib/glue.rs
index 901a06bfe14..169ea08d254 100644
--- a/ports/geckolib/glue.rs
+++ b/ports/geckolib/glue.rs
@@ -634,9 +634,9 @@ pub extern "C" fn Servo_Shorthand_AnimationValues_Serialize(shorthand_property:
 }
 
 #[no_mangle]
-pub extern "C" fn Servo_AnimationValue_GetOpacity(value: RawServoAnimationValueBorrowed)
-     -> f32
-{
+pub extern "C" fn Servo_AnimationValue_GetOpacity(
+    value: RawServoAnimationValueBorrowed
+) -> f32 {
     let value = AnimationValue::as_arc(&value);
     if let AnimationValue::Opacity(opacity) = **value {
         opacity
@@ -645,6 +645,13 @@ pub extern "C" fn Servo_AnimationValue_GetOpacity(value: RawServoAnimationValueB
     }
 }
 
+#[no_mangle]
+pub extern "C" fn Servo_AnimationValue_Opacity(
+    opacity: f32
+) -> RawServoAnimationValueStrong {
+    Arc::new(AnimationValue::Opacity(opacity)).into_strong()
+}
+
 #[no_mangle]
 pub extern "C" fn Servo_AnimationValue_GetTransform(value: RawServoAnimationValueBorrowed,
                                                     list: *mut structs::RefPtr<nsCSSValueSharedList>)