Kent are "disappointed" that Jordan Cox, the wicketkeeper-batter who toured Pakistan with England's T20I squad last year, has turned down the offer of a contract extension in order to join Essex.
Cox informed the club on Monday of his desire to leave at the end of this season and has signed a three-year deal with Essex where he is seen as a long-term replacement for Dan Lawrence, who is leaving for Surrey.
Cox went to school in Essex - at Felsted, 10 miles north of Chelmsford - where he worked closely with Jason Gallian. Gallian became chair of Essex's cricket committee earlier this year and the pair have maintained a good relationship.
Cox's departure is a major blow for Kent, the county where he has played since the age of 10. He played a significant role in the club's Blast win two years ago, scoring 58 not out in the final before setting up a remarkable relay catch during Somerset's run chase with sensational athleticism on the boundary rope.
"We're disappointed that Jordan has decided to move on from Kent next year," Paul Downton, Kent's director of cricket, said in a terse club statement. "He has made a name for himself as a Kent cricketer and has been extremely well supported by the club."
Downton, who is leaving his role at the end of the season, added: "That said, we would like to thank Jordan for his contributions to Kent Cricket and wish him well with his cricket in the future."
He is the second keeper-batter academy graduate to leave Kent in the last 12 months, after Ollie Robinson joined Durham at the end of last year. Robinson has thrived since moving north, scoring three Championship hundreds this season and finishing the Blast as Durham's top run-scorer.
There has been a logjam of wicketkeeper-batters at the county, with club captain Sam Billings generally taking the gloves when he has been available - though Cox had kept wicket in Kent's last six Championship games with Billings taking a break from first-class cricket after a lean run of form.
Billings tweeted on Friday night that he was "disappointed" to see Cox leave the club, but added: "As a club I don't think we could have supported his journey any more & at times prioritised his development over others.
He added: "Opportunities for young players now are endless. Good advice & support networks are paramount to navigate through a career especially in the early (most important) stages of development."
Essex have used three different wicketkeepers this year - Adam Rossington, Michael Pepper and Will Buttleman - but none has scored heavily in the Championship. Cox has not been given any guarantees around keeping wicket, but is likely to have opportunities with the gloves at some stage.
Anthony McGrath, their head coach, said: "I am delighted that we have been able to secure the signing of Jordan, who is a young, hungry cricketer looking to impress in all formats.
"He will add real depth and quality to our batting line-up, as well as strengthening our wicket-keeping ranks too, and we are all very much looking forward to working with him."
Cox said it was "a real honour" to sign for Essex, adding: "The team is full of talent, they are going places, and I can only see the group getting better over the coming seasons. I'm excited to join them and contribute to what I hope will be a successful future.
"I'd like to thank everyone at Kent for everything they have done for me to get me where I am today. I'll miss my team-mates, coaches and the staff at Kent but I feel that now is the time for me to move on.
"The club will always hold a special place in my heart, and I will always look back on my time here fondly. I will continue to give my all for Kent during the rest of my time here."