Robyn Lawley has urged designers not to be ''fearful'' of using curvier models.

The brunette beauty - who starred in the pages of the latest Sports Illustrated Swimsuit Issue - believes sizeist attitudes in the fashion industry could be changed if designers created larger sample sizes and included bigger girls on the catwalk.

Robyn, who also has her own swimwear line, said: ''Designers need to not be so fearful of using a few models that are a different size on the catwalk. They expect you just to fit into these sample sizes. They say, 'Yeah, you don't look like a size 12.' I've got a 42-inch hip, my friend, this is not going to fit.

''I can't get clothes for events. I'm very excluded from a lot of that, and it sucks. If designers had more sample sizes, they would make the magazines shoot size 8 on a size 8... I don't really understand why. I used to think sample sizes were made into a 0. But as a designer myself, I make the sample sizes whatever I want. Why are we so focused on having the girl fit the clothes rather than the clothes fit the girls?''

At a Size 12 (UK size 16) Robyn is considered a plus-size model and believes fellow voluptuous beauty Kate Upton has helped pave the way for curvier models.

She also credits designers Ralph Lauren, Calvin Klein and Sports Illustrated for using above sample-sized girls in their campaigns.

Robyn, 25 - who is expecting her first child with lawyer Everest Schmidt - told The Cut. ''MJ Day, assistant managing editor of Sports Illustrated, said it was like the Kate Upton effect.

''Everything happened in a flow and is finally happening. At the end of the day, I'm a size that they're not used to. It's quite a process and I am quite stoked they were really willing to go down that route... People don't know how hard it is to break a mould. It's a step in the right direction - I'm proud of Ralph Lauren, Calvin Klein, Sports Illustrated - and it needs to happen faster. We're hoping it does.''