Khloe Kardashian (Pic: Instagram)

Khloe Kardashian "felt pressure" to be like her sisters - Kim Kardashian West and Kourtney Kardashian - when she was growing up.

As 'Keeping Up With The Kardashians' continued to evolve, the 33-year-old television personality felt she should be following the success of her older sisters - Kim Kardashian West and Kourtney Kardashian - and admitted to signing some questionable endorsements to feel like she fitted in.

She shared: "I didn't start to really understand the opportunity the series presented until the fourth or fifth season. I was young, and I didn't care as much. The truth is that I was heavier then too, so not a lot of endorsements were coming my way. Brands would prefer to align themselves with Kim or Kourtney, which I was totally fine with because I was still along for the ride.

"But it's also a very sad thing to realise that most brands are interested only in pretty, cute, in-shape girls. There were things I did back then that made me think, Why am I doing this? I once did a deal with a tampon company, and I was like, 'Why am I so thirsty?' But I was young, and you feel pressure; you see your sisters getting deals and you're like, 'Should I be doing something? Is a pad commercial all I can get? Well, OK then.'"

Read: Khloe Kardashian jealous of Kylie Jenner's success?

However, Khloe is much more confident in herself now and started being more selective with her opportunities when they flooded in after she tied the knot with Lamar Odom.

She added in an essay for Glamour magazine: "The older you get, and the more comfortable you become in your skin, the more you begin to think about what makes sense for you.

"When I started getting in shape and when I first got married [to now-ex Lamar Odom, the basketball player], a different amount of attention came my way. Because I had already seen my sisters go through it, I was able to be pickier about my opportunities."