Everton No2 Irvine named Preston manager
The Scot, who had been working as David Moyes' assistant at Goodison Park, has agreed a three-and-a-half year deal with the club.
North End chairman Derek Shaw told the club's official website: "We're very pleased that Alan will be joining us, he's ready to have a crack at management.
"He's got a reputation of being a top-notch coach, his work ethic is amazing. He's worked with David Moyes and I know the amount of games they take in, you see them all over the country."