The 30-year-old, who made the last of his 12 international appearances for the Proteas in 2016, already has county experience after four seasons with Welsh club Glamorgan.
The County Championship will return next year in a group-stage format after it was scrapped this season due to the coronavirus pandemic, the England and Wales Cricket Board said.
Reigning county champions Essex extended their red-ball dominance after edging the first in what could be a new tradition of first-class season deciders for English counties.
Shoaib Akhtar says only 'one or two' Pakistan teammates mistreated Danish Kaneria for his religious identity
Akhtar said he immediately stepped in to stop those players from discriminating against Danish Kaneria, which shows that as a society, they don't indulge in racial discrimination
Lyon is the latest Australian to sign with an English county for the 2020 season, with Travis Head joining Sussex, Cameron Bancroft at Durham and Peter Siddle returning to Essex
Sri Lanka great Kumar Sangakkara set to captain MCC against county champions Essex at Galle International Stadium
Sangakkara — whose 15-year international career encompassed 134 Test appearances and over 400 one day internationals — will lead out his side in the English domestic season's traditional curtain-raiser at the Galle International Stadium
Essex crowned England's county champions after Ryan ten Doeschate's men see off spirited Somerset on final day
Essex won England's County Championship for the second time in three years after holding off a spirited charge by Somerset on the final day of the season
T20 Blast: Captain Simon Harmer's all-round performance helps Essex beat Worcestershire in dramatic final
Essex captain Simon Harmer produced a match-winning cameo with the bat to lead his team to victory over Worcestershire on the final ball of Saturday's T20 Blast final.
UK airline fines woman Rs 70 lakh for causing hijack scare on Turkey-bound flight, bans her for life
Chloe Haines, a Costa Coffee worker who was travelling with her wheelchair-bound grandmother, caused a hijack scare when she attempted to open the aircraft door and storm the cockpit during a flight from London Stansted to Dalaman in Turkey on 22 June.
De Villiers kept on hammering Essex bowlers all around the park and he went on to score 88 runs off just 43 balls. This knock by the right-handed batsman enabled Middlesex to register an easy win by seven wickets with three overs to spare
Pakistan's Danish Kaneria has finally admitted his role in a fixing scandal that led to the imprisonment of former Essex team-mate Mervyn Westfield after six years of denials
James Foster rose through the ranks at Essex from his days as a junior cricketer when he also represented England Under-19s.
India's Murali Vijay struck a fine century in a dream county debut, guiding Essex to a comfortable eight-wicket victory over Nottinghamshire in County Championship Division One match at Trent Bridge
Vijay Hazare 2018: Vijay Shankar to lead Tamil Nadu squad bereft of international stars Dinesh Karthik, R Ashwin and Murali Vijay
The Vijay Shankar-led team was announced on Tuesday by the Tamil Nadu Cricket Association's selection committee.
The hard-working Peter Siddle played the last of his 62 Tests in November 2016, and it appeared he had worn the Australian baggy green cap for the last time.
Alastair Cook marks swansong Test with ton, becomes only fifth batsmen to score century on debut and final match
Alastair Cook scored his 33rd Test century on Monday in his farewell international match at the Oval, bringing the curtain down on a record-breaking England career in style.
"He's (Alastair Cook) had so many games as captain, a record there, as a player he's the record run-scorer in history, and he's a calm, balanced and fair person, so I think we've got to try to tap into that knowledge and wisdom without a doubt," said national England selector Ed Smith.
Senior India opener Murali Vijay will be playing three matches for Essex in the final phase of the division one of English County Championship, the BCCI announced on Saturday.
Australia pacer Peter Siddle signs fresh two-year deal with Essex after fruitful run at County Championship
Australia bowler Peter Siddle signed a two-year deal at Essex on Friday following his successful spells at English county this season.
"Now it’s about us as a team giving him (Alastair Cook) an opportunity to go out in the best way possible," England skipper Joe Root told reporters at The Oval.