Hull have announced that 12BETuk will be the club’s official shirt sponsor.
The seven-figure deal with the bookmakers is the largest in the Premier League club’s 110-year history and will run until the end of the 2015/16 season.
Hull are also working on independent sponsorship deals for the club's cup and European matches as they attempt to build on their impressive return to the Premier League and run to the FA Cup final.
Commercial director Simon King said: “We are delighted to be working with 12BET.
"Having a global brand like 12BET with a great history of working in football is very exciting.
"This deal represents how far the club has come on the field and from a commercial perspective in the recent years."