Jason Patric 'Always Believed' He Would Win Appeal For His Son

Jason Patric says he "always believed" he would win the appeal that a Los Angeles Court of Appeals handed the "Lost Boys" actor in his fight to be recognized as the father of his 4-year-old son Gus.

"It's been 64 weeks since I've seen Gus and I always believed we were going to win this appeal because it was just wrong, the decision," Patric said today on " Good Morning America. "I had faith in the process."

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Patric, 47, fathered Gus with his former girlfriend, Danielle Schreiber. They conceived the child via in-vitro fertilization, or IVF, and co-parented for more than a year before their relationship ended.

Schreiber and her legal team have said that Patric never signed a birth certificate and that Patric offered to donate sperm after the two broke up "under the express condition" that it be kept secret.

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"It's actually misinformation. It's the opposite," Patric said today on "GMA." "I signed forms at the IVF clinic that say 'intended parent.' I'm on school forms. I'm on all forms as the parent."

"There's no document that exists that I've given up my rights and if I've ever wanted to do that, if that was the agreement, which they allege, I would certainly want to sign the document like that to protect myself financially," he said. "It was the opposite. I tried to have a child."

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Wednesday's court ruling in Patric's favor puts the custody battle back in the position it was before an earlier court decision found he was a sperm donor with no parental rights and a judge barred Patric from seeing his son.

"At this point we're going to go back into court next week and ask the court to reinstate Jason's visitation," said Patric's attorney, Fred Silberberg. "He had been spending time with Gus pursuant to a court order while the case was pending, seeing him five days a week plus two days video chat."

"We're going to go back and deal with that phase and then there will be a trial set on whether he meets the standard of holding the child out as his own and receiving Gus in his home, which we believe we can meet," Silberberg said.

Schreiber's legal team issued a statement to ABC News in response to Wednesday's ruling indicating that they plan to continue the legal battle.

"We respectfully disagree with the Court of Appeals and we are exploring our options and should make a decision shortly," the statement read, in part.

Patric has taken his fight for Gus all the way to California's Assembly Judiciary Committee, where last August he lobbied for a bill that would allow him and others in similar situations to seek paternity rights. He has also established an organization, " Stand Up for Gus," with a mission to reform the family court system and provide legal aid for families involved in custody cases.

The actor said it still "haunts" him that he told Gus the last time he spoke with his son that he would "see you tomorrow."

"In his mind I just disappeared and I didn't tell him the truth. It's something I deal with every day," Patric said. "I need to see him. I need to hold him. I need the connection."

"I have been a dad. I'm going to continue to be a dad," Patric said. "You can't ever abandon a child."

ABC News' Michael Rothman and Bonnie McLean contributed to this report.