O'Neil helped Bournemouth secure their top-flight survival last season, steering them to a 15th-placed finish in the league after taking over from Scott Parker, but their form trailed off towards the end of the campaign.

Iraola joins Bournemouth after guiding Rayo Vallecano to an 11th-placed finish in LaLiga last season, following a successful three-year spell at the Spanish club.

"We're so excited to welcome Andoni to the club," Bournemouth owner Bill Foley said. "With his contract in Spain coming to an end this summer we wanted to act quickly.

"We have identified a number of targets in the transfer market, which along with our January additions will supplement our strong playing squad to give Andoni the best chance to consolidate our Premier League status and keep progressing."

American businessman Foley, who took over Bournemouth in December, said in an earlier statement that the change in manager would help the club better execute their strategy in the coming months.

"Gary's achievement last season is one I will always be grateful for. This has been a difficult decision, but it has been made with great consideration to best position ourselves ahead of the coming season," he said.

"As a club, we have put plans in place for long-term success with improvements being made to infrastructure, most notably the development of a new state-of-the-art training facility and the ongoing discussions around upgrades to our stadium.

"We... believe this change in direction will provide us with the best platform from which to build."