Eric Roberts is opening up about his family's complicated history. 

The Runaway Train alum got candid about how his longtime battle with cocaine addiction impacted his relationship with his 33-year-old daughter Emma Roberts, who he shares with ex Kelly Cunningham. 

After Eric—who tied the knot with wife Eliza Roberts in 1992—split with Kelly when Emma was a baby, he lost the subsequent custody battle, writing in his new memoir Runaway Train: Or the Story of My Life So Far, per People, “Of course, the biggest consequence of my drug use was losing Emma.”

And to make the court's ruling even more difficult at the time, the 68-year-old recalled his estranged sister Julia Roberts taking Kim's side in the legal case due to his struggle with addiction. In fact, he credited her decision to side with Kelly with further throwing a wedge in their complicated relationship—though now he agrees that the Pretty Woman star made the right choice. 

“I imagine I will remain as Julia’s brother and Emma Roberts’ dad for the rest of my life,” he continued. “I’d like to make good on that, to move aside proudly and with grace. That’s part of the reason for writing the book.”

And while Eric—who got sober in 1995 after attending court-ordered rehab for 18 months—confessed that his relationship with his daughter has faced some challenges, the Dancing With the Stars contestant couldn't be more proud of Emma's acting achievements, which include starring roles on shows Scream Queens and American Horror Story, as well as in films We're the Millers, Madame Web and Holidate. 

"I'm in love with my daughter's work these days," Eric said during a July appearance on the Still Here Hollywood podcast. "I can't believe how great she's become. I'm so proud of her I can't see straight."

As for Emma? She hasn't spoken publicly on where her relationship with her dad stands, but she previously shared how her strong bond with her aunt Julia led her to a career in Hollywood. It all started when the Oscar winner brought her along to the set of her 2000 film Erin Brokovich. 

"When night fell, I'd run and hide in her makeup trailer and hear, 'Where's Emma? It's time for bed! She has to go home!'" Emma recalled in a 2016 interview with Allure. "I remember it feeling like summer camp, just the feeling of creativity."

For free and confidential help for those facing mental and/or substance use disorders, call the Substance Abuse and Mental Health Services Administration (SAMHSA) national helpline at 1-800-662-HELP (4357).