The purpose of this article is to explore the present COVID-19 crisis, which has affected fast-fashion. Global fast-fashion consumers have lost hope to revamp their wardrobe due to the broken supply chain network and the fear to visit the stores for purchase. The research intends to provide a detailed framework for the fast-fashion brands to strategically plan for post-COVID-19 business normality leading to sustainability. For the development of the model, careful investigation of the articles was carried out. This research is purely qualitative in nature depending on secondary data.In the post-COVID-19, the e-commerce industry will boom and those fast-fashion brands, which are already in the e-commerce platform, have to know the Percentage of Concentration (POC) in which they have to concentrate so that there are no wastages and spillover effects. Hence, marketing agility and e-commerce agility becomes the foundation for fast-fashion brands if it has to recapture its leadership position in the post COVID-19 pandemic. Fast-fashions have to follow the art of rethinking to replan and reimplement new strategies to revamp the business.