Lisa Marie Presley's Ex-Husband Michael Lockwood Wants to Rep Twins in Court

Lisa Marie Presley's ex-husband Michael Lockwood has filed legal docs to allow him to represent the interests of their twins in an upcoming critical hearing that involves millions of dollars.

According to the docs, obtained by TMZ, Lockwood is asking a judge to appoint him guardian ad litem -- giving him authority to speak for his 14-year-old girls in a hearing over Lisa Marie's trust.

TMZ broke the story ... that trust became flush with cash when Elvis's only child died January 12. As we reported, Lisa Marie had 2 life insurance policies -- one for $25 million and another for $10 million.

Sources connected to the family tell TMZ ... there's a lot of behind-the-scenes drama over who will administer and control the trust. As we reported, Priscilla Presley was a trustee but Lisa Marie booted her from that position several years before her death, and made her oldest daughter Riley the trustee in Priscilla's place.

Our sources tell us Priscilla is going to challenge the validity of the trust, claiming the change in trustees was not properly made. Riley, we're told, does not want Priscilla to take the reins, and this set up a family battle.

As we reported, the beneficiaries of the trust are Riley and the twins, Harper and Finley.