Phillip Cocu has been appointed Derby's new boss on a four-year deal.
The former Holland international replaces Frank Lampard, who became Chelsea manager on Thursday.
Cocu told the club's official site: "I am pleased and honoured to confirm that Derby County will be my new club and can't wait to meet with the team and the fans to start this adventure together."
Cocu's last senior post was in Turkey with Fenerbahce but he lasted just four months and was sacked in October following one of the club's worst starts to a season, where he won just three times in 15 games.
Former midfielder Cocu played for Barcelona and won 101 caps for Holland.
He guided PSV Eindhoven to three Dutch league titles during five full seasons in charge between 2013 and 2018 before a short spell in Turkey at Fenerbahce last season.
Derby executive chairman Mel Morris said: "We are delighted to welcome Phillip Cocu as our new manager.
"We are continuing to develop our philosophy at Derby County and from the first conversation with Phillip, and his team, it was very clear they share similar views.
"The fit is strong. We want to build on the momentum that we have in our style of play, our club values, and the increasingly important role of our academy. Phillip and his team understand the need and benefits of this approach."
Derby's new coaching staff have joined the first-team squad in Florida for a 10-day training camp with two friendly matches also scheduled.
