Online retailer boohoo.com has acquired rival fashion website Pretty Little Thing and upgraded its profit guidance following bumper Black Friday trading.

The fast-fashion firm will pay £3.3 million for 66% of Pretty Little Thing, with the remaining 34% being retained by the management team headed up by boss Umar Kamani.

Boohoo chairman Peter Williams said: "Pretty Little Thing was always going to be a natural fit with boohoo. Umar and his team are to be congratulated for creating a fantastic brand, which complements boohoo's own.

"We believe this is an excellent opportunity to extend the group's overall customer appeal."

Revenues at Pretty Little Thing grew by more than 400% to £17 million last year and the company delivered revenue of £19 million in the six months to August 31 2016.

Boohoo, meanwhile, said that its trading across the Black Friday weekend was strong and "peak season trading continues to be encouraging".

The firm now expects to deliver revenue growth of between 38% and 42% for the full year, up from previous guidance of between 30% and 35%, while its earnings margin is also expected to grow by between 11% and 12% versus earlier estimates of around 11%.