Lady Gaga has slammed her "lifelong friends" for "betraying" her.

The "Marry the Night" hitmaker admitted she has had a "challenging" year marred by creative struggles - including criticisms her "Born this Way" single was too similar to Madonna's "Express Yourself" - professional disagreements and her own body image issues in an open letter to her fans.

"Today is a really happy day for me. The past year was a challenge, and I'm so happy to have my spirit back. I felt in chains at times," she wrote on her Little Monsters website.

In what is believed to be a reference to her dispute with director Joseph Kahn over a scrapped "Born this Way" video treatment, she added, "Whether it be the record label disagreeing with me on single choices, or directors who could only create an idea of 'gaga' or what I've 'done before' and not able to move forward, and there was also of course the incessant dragging of the most important single of my career in dead-beaten-horse-mud. Then there were all the personal moments. Betrayed by lifelong friends, mentors I've had for years suddenly taking advantage of me, and a massive struggles with my body image.(sic)"

However, the "Edge of Glory" hitmaker reassured her fans she now feels "blessed" to find her life back in control and heading in the right direction.

She ended the letter by saying, "I've grown and left most of these things behind, the monsters of fame are very real. But I wanted to thank you for [bearing] with me a little bit. Today's film [Fame fragrance trailer] is what happens when there is love and respect amongst creatives, teams, management. This project was run solely by the Haus of Gaga, Atom Factory, and Steven Klein's fantastic team. I am feeling blessed to have removed those from my life driven by money and luxury, its all about the art of it. I feel free today. Thank you for always being there for me monsters."