(Olympiad Champs English Class 8 with Past Olympiad Questions ...) with bells on When you are delighted and eager to go somewhere, you are said to go with bells on.
There are some ideas of translation in Word Reference, but they are all unsatisfactory (Word reference). "Joyeusement" is close but not idiomatic, and "avec le ban et l'arrière ban" is not at all the idea.
I can't think of a true idiom that would correspond sufficiently well to "with bells on".
If you are replying to someone who has extended an invitation to you, a nice rendering is "se faire un plaisir de", used in the future or in the near future ("je vais me faire un plaisir de"); however, it is somewhat formal, and I believe that with "bells on" is a little colloquial and possibly expressive of more buoyant enthusiasm. This is an expression that is not restricted for use concerning events where one is invited or where one is a participant: it can be used for any prospect of doing something interesting. There are two other similar expressions that I know of, "être heureux de" and "attendre avec impatience". Those forms are however self-explanatory.
Nous nous ferons un plaisir de venir vous voir ce lundi.
Je me ferai un plaisir de venir à votre partie d'anniversaire, mais je serai forcé de venir seul, Delphine est malade.
Les enfants seront heureux de venir se baigner chez vous avec vos fils et leurs amis.
Nous attendrons avec impatience le jour de nous rendre à votre soirée.
Other form, more enthusiastic, downright colloquial
- Je voudrais déjà être au jour de ta partie, je suis impatiente d'y arriver.
Other form, current register but expressive of an extreme enthusiasm (much stronger than "with bells on")
- Elle est tout feu tout flamme à l'idée d'aller à ton pique nique.