diff --git a/src/UI/Timeline/AnimationTimeline.gd b/src/UI/Timeline/AnimationTimeline.gd
index 80378f1dd..81a9cecca 100644
--- a/src/UI/Timeline/AnimationTimeline.gd
+++ b/src/UI/Timeline/AnimationTimeline.gd
@@ -1046,7 +1046,7 @@ func _on_MergeDownLayer_pressed() -> void:
 	bottom_layer.visible = true
 
 
-func _on_OpacitySlider_value_changed(value: float) -> void:
+func _on_opacity_slider_value_changed(value: float) -> void:
 	var new_opacity := value / 100.0
 	for idx_pair in Global.current_project.selected_cels:
 		var layer := Global.current_project.layers[idx_pair[1]]
@@ -1068,13 +1068,16 @@ func _on_timeline_settings_visibility_changed() -> void:
 func _cel_switched() -> void:
 	_toggle_frame_buttons()
 	_toggle_layer_buttons()
+	# Temporarily disconnect it in order to prevent layer opacity changing
+	# in the rest of the selected layers, if there are any.
+	opacity_slider.value_changed.disconnect(_on_opacity_slider_value_changed)
 	_update_layer_ui()
+	opacity_slider.value_changed.connect(_on_opacity_slider_value_changed)
 
 
 func _update_layer_ui() -> void:
 	var project := Global.current_project
-	var layer_opacity := project.layers[project.current_layer].opacity
-	opacity_slider.value = layer_opacity * 100
+	opacity_slider.value = project.layers[project.current_layer].opacity * 100
 	var blend_mode_index := blend_modes_button.get_item_index(
 		project.layers[project.current_layer].blend_mode
 	)
diff --git a/src/UI/Timeline/AnimationTimeline.tscn b/src/UI/Timeline/AnimationTimeline.tscn
index 37b94132b..57daca63c 100644
--- a/src/UI/Timeline/AnimationTimeline.tscn
+++ b/src/UI/Timeline/AnimationTimeline.tscn
@@ -1034,7 +1034,7 @@ color = Color(0, 0.741176, 1, 0.501961)
 [connection signal="pressed" from="TimelineContainer/TimelineButtons/VBoxContainer/AnimationToolsScrollContainer/AnimationTools/AnimationButtons/LoopButtons/LoopAnim" to="." method="_on_LoopAnim_pressed"]
 [connection signal="value_changed" from="TimelineContainer/TimelineButtons/VBoxContainer/AnimationToolsScrollContainer/AnimationTools/AnimationButtons/LoopButtons/FPSValue" to="." method="_on_FPSValue_value_changed"]
 [connection signal="gui_input" from="TimelineContainer/MainBodyPanel/MainBodyVBoxContainer/TimelineScroll/MarginContainer/LayerFrameHSplit" to="." method="_on_LayerFrameSplitContainer_gui_input"]
-[connection signal="value_changed" from="TimelineContainer/MainBodyPanel/MainBodyVBoxContainer/TimelineScroll/MarginContainer/LayerFrameHSplit/LayerContainer/MarginContainer/OpacitySlider" to="." method="_on_OpacitySlider_value_changed"]
+[connection signal="value_changed" from="TimelineContainer/MainBodyPanel/MainBodyVBoxContainer/TimelineScroll/MarginContainer/LayerFrameHSplit/LayerContainer/MarginContainer/OpacitySlider" to="." method="_on_opacity_slider_value_changed"]
 [connection signal="resized" from="TimelineContainer/MainBodyPanel/MainBodyVBoxContainer/TimelineScroll/MarginContainer/LayerFrameHSplit/LayerContainer/LayerVBox" to="." method="_on_LayerVBox_resized"]
 [connection signal="timeout" from="AnimationTimer" to="." method="_on_AnimationTimer_timeout"]
 [connection signal="close_requested" from="TimelineSettings" to="." method="_on_timeline_settings_close_requested"]