Although Hilary Duff’s marriage to former NHL star Mike Comrie is at an end, the custody battle is just ramping up.

TMZ reports Mike has responded to the actress’ divorce petition, and is seeking joint custody of their 3-year-old son, Luca.

In Hilary’s original filing, she sought primary custody of Luca, with Mike only being allowed visitation.

Although both parties acknowledge having signed a prenup, the document may not have provided a clear child custody arrangement in the event of divorce.

As a result, this may be a long, drawn-out process for everyone involved.