Khloe Kardashian forged her parents' signatures to change schools.

Khloe Kardashian

Khloe Kardashian

The 31-year-old reality star struggled with her exams and found it difficult to cope once her older sisters Kourtney Kardashian and Kim Kardashian West had left high school, so wrote documents claiming to be from her mother Kris Jenner and father Robert Kardashian - who passed away in September 2003 - in order to get a transfer, much to their fury.

She recalled: "I went to Marymount in ninth grade, while Kourt and Kim were there, but after they left, I felt like I had no one to be with.

"I struggled really hard in school, so I forged my parents' names to enrol in Alexandria Academy.

"My dad was livid when he found out. I was so scared I was shaking."

As the younger sister, Khloe struggled to forge her own identity because she was always being compared to Kim, 35, and Kourtney, 37.

She told Star magazine: "They were so popular. I didn't care about being popular in school. I was nice to everyone.

"While I loved having my built-in group with Kim and Kourtney, it was hard for me at times.

"They may have already graduated when I got to school but I remember teachers would always exclaim, 'You're their sister?' I didn't have my own identity and was compared to them."

And the 'Keeping Up With the Kardashians' star found it hard when she was the subject of cruel jibes about her size when she and her family found fame with their reality show.

She said: "Growing up, I was always chubby.

"I knew I didn't look like my sisters and I didn't have those shapes but I didn't think that was wrong...

"I didn't know I was the 'fat' sister until I went on TV and the media started saying that about me.

"Being compared to my sisters was something I was used to. But being compared in such a harsh way... I wasn't fat, I wasn't obese, but I let society make me believe I was."