May I stand up for a Catholic who is marrying outside of the Church?

My friend who is catholic asked me to stand up in her wedding which will be in the Lutheran Church to her Lutheran fiancee, I do not know if she was confirmed Catholic, as a Catholic should I accept or decline?

Dear l,

To be in a wedding party is to be an offical witness to the validity of the wedding. As a Catholic you may not give witness to the wedding of another Catholic who is marrying outside of the Church. Such a marriage is invalid in the eyes of the Church.

Fr. Vincent Serpa, O.P.

DISCLAIMER: The views and opinions expressed in these forums do not necessarily reflect those of Catholic Answers. For official apologetics resources please visit