Kate Bostock, former Marks & Spencer fashion boss, is to join the board of etail powerhouse Asos.

Asos confirmed this morning that Bostock will join in January as executive director, product and trading.

She was previously executive director, general merchandise, at M&S, and has also previously held senior roles at George at Asda and Next.

The appointment comes almost a year after speculation first emerged that she would join Asos, and follows her departure from M&S at the start of this month.

Bostock, 55, joins Asos as product director Robert Bready exits the business to “pursue fresh challenges”. In July, Asos denied Bready was set to leave the business after selling 143,125 shares for £2.6m. He has been at the retailer for seven years.

Speculation surrounding Bostock’s new role began in November last year but died down before reigniting in July.

Asos chief executive Nick Robertson said: “Our product and trading team now exceeds 350 people. We are fortunate to have Kate bring us her wealth of experience from some of the biggest names in retailing as we strengthen our retail disciplines and put in place the structures needed to manage the next phase of our growth.”

Bostock said: “Asos is a phenomenon and I’m in awe of the story. With its unique mix of own label and fashion-forward brands delivered online and increasingly through mobile, the potential for Asos globally is huge. I’m very excited to be joining at such a time of immense opportunity.”

In her time at M&S Bostock drove a more fashion-led offer across the retailer’s labels as well as sharpening up navigation of the sub-brands which include Autograph, Limited and Blue Harbour. Despite the bulk of her experience lying in clothing, she made great strides in improving the non-fashion offer, recognising the opportunities open to the retailer.

She was also in the running for the chief executive role before it went to Marc Bolland in 2010.