Gildan Activewear Inc. agreed to buy US underwear maker Hanesbrands Inc. — aiming to double its annual sales — for about $2.2 billion in cash and stock.

In a major move to consolidate the basic side of the apparel industry, Gildan Activewear Inc. has agreed to buy HanesBrands Inc. in a cash and stock deal that values the innerwear giant stock at $2.2 billion.

The deal would nearly double Gildan’s revenue, but there could be antitrust hurdles because both companies sell underwear, hosiery and shirts.