One is blonde, the other brunette. While one excelled in volleyball, the other wanted to become a photographer.

Gigi and Bella Hadid at the CFDA Fashion Awards after party in New York, in Jun 2015

But whatever their differences they have at least two things in common.

They are both going head to head at the Royal Albert Hall tomorrow for the title of world’s greatest model.

The award is for the female or male model that has “contributed most to the international fashion scene in the past year and has demonstrated influence beyond the catwalk”.

Should either 21-year-old Gigi or Bella, 20, pick up this somewhat grandiose title at the end of tomorrow’s glittering gala evening it will represent the high point in parallel careers that have seen them come to dominate both the catwalks and the covers of the world’s glossiest magazines.

Naturally the sisters are also huge on social media - Gigi has 26 million followers on Instagram alone - lending them an appearance of intimacy with their fans which earlier generations of supermodels could never hope to achieve.

Caroline Rush CBE, Chief Executive, British Fashion Council, which runs tomorrow's awards, said either one would be a worthy winner.

“Bella and Gigi are two distinctive personalities who seem to have found their feet so young,” she said.

“Both are incredibly talented models but the nominations show that our voting panel also recognises the power of social media. Both young women are brilliant examples of businesswomen who have been able to harness the consumer demand to engage with the personality behind the brand.”