Sinclair was born to a Kiwi father of English descent and Dutch mother in Manama, Bahrain.
[1] Due to her father's occupation, Sinclair has spent her childhood living in various places, including San Francisco, Hong Kong and England.
Sinclair's modelling career began during the second year of university, when she was scouted for a fashion show in a regional museum.
Following her victory, she earned a contract at MTA Models, the cover of Dutch Glamour Magazine, a L'oreal Paris Campaign, and 75,000 Euros.
[4][5] She was featured in campaigns such as Zuneta and she starred in the short film "Treasure Box" by Gemma Booth.
[6] She even participated in London Fashion Week walking for Eun Jeong, Jasmine Di Milo, Future Classics, Dean Quin and Ashish.
Due to her success in England, she decided to move to London and made her mother agency Union Models.
[22] She was also featured on the cover of Health & Beauty in England as well as appearing in Relapse Magazine and Alt for Damerne.