Lily Collins has penned an honest open letter to her father, musician Phil Collins, and written about their relationship in a new book.

Writing in her book Unfiltered, the Golden Globe-nominated actress said: "Many of my deepest insecurities stem from these issues with my dad."

In the open letter she said she forgave the Genesis drummer for "not always being there" and "not being the dad I expected", the BBC reports.

Collins left Lily's mother Jill Tavelman when the actress was five, and she said a "terrible disconnect" developed between her and her father - who has four other children - as she grew up.

"He may have still been alive, but most of the time it felt as if her were completely gone," 27-year-old Collins wrote in the book. "I knew he loved me, yet he wasn't physically around to tell me.

"He assumed everything was always fine because I never said otherwise. It established a detrimental pattern. And I've realised that many of my deepest insecurities stem from these issues with my dad. It's taken me more than a decade to resolve some of them (others I'm still resolving) and to finally build up the courage to speak my mind to him."

In the open letter, the Love, Rosie actress also assured her father that she will always need him and "always be your little girl", but added: "We all make choices and, although I don't excuse some of yours, at the end of the day we can't rewrite the past. I'm learning how to accept your actions and vocalise how they make me feel.

"I accept and honour the sadness and anger I felt towards the things you did or didn't do, did or didn't give me.

"I forgive you for not always being there when I needed and for not being the dad I expected. I forgive the mistakes you made. And although it may seem like it's too late, it's not. There's still so much time to move forward."