Jamie Overton will leave Somerset at the end of this season after signing for Surrey on a three-year deal.
Overton, one of the brightest fast-bowling talents in the country, was offered new terms by Somerset but has opted to make the move to The Oval, citing the need for a "fresh challenge to test myself and see how good I can be".
He was named in Somerset's team for their Bob Willis Trophy opener against Glamorgan, and will play for the club for the rest of the season.
"Jamie is a genuine quick bowler and his pace and bounce gives a real X-factor to his armoury," said Alec Stewart, Surrey's director of cricket. "His style of bowling will be well suited to The Kia Oval pitches. He has all the necessary attributes to play for England and we will be working hard to help him achieve that goal."
Overton said: "From the moment that Alec made contact and talked me through the opportunity, I was excited about coming to Surrey. I'm obviously aware of the club's history and success and these were all major attractions for me in moving from Somerset.
"I've got high aspirations and I'm hoping that being here and working with all involved on and off the pitch I can achieve those dreams. I'm obviously very disappointed to be leaving Somerset. I've had a great nine years at the club and loved every minute of it, but I feel it is time for a fresh challenge in cricket."
Overton's move may come as a surprise given Somerset's recent success, but he has rarely been part of their first-choice attack, with twin brother Craig, Lewis Gregory and Josh Davey all ahead of him in the County Championship pecking order in recent years. They recently strengthened their seam-bowling stocks with the additions of Jack Brooks and Vernon Philander (whose deal has now been cancelled due to the Covid-19 pandemic) and Overton had to go on loan to Northamptonshire last season to get first-team cricket.
He is highly-regarded by the England management, and was part of the 30-man training group ahead of the West Indies Test series following regular appearances in Lions squads, including as a non-playing reserve in Australia last winter.
While Surrey have a vast number of seamers on their books, they are regularly without the Curran brothers due to international call-ups and seem unlikely to extend Morne Morkel's contract once Kolpak registrations are cancelled at the end of the year. Liam Plunkett and Jade Dernbach are both primarily limited-overs bowlers, while Stuart Meaker left for Sussex at the end of last season.
For their Willis Trophy opener, they are down to the bare bones, with allrounders Jordan Clark and Rikki Clarke, 19-year-old James Taylor and Matt Dunn the only available seam options. Gus Atkinson, Nick Kimber and Conor McKerr are not currently match fit, with Reece Topley also on England duty.
For Somerset, there are concerns that Overton may not be the only departure this year. Twin brother Craig is also out-of-contract - though is certain to be offered new terms - while Paul Farbrace is hopeful that he can lure Dom Bess to Warwickshire.