Four-time English Premier League champion Petr Cech is only the sixth Chelsea player to move directly to London rivals Arsenal.
The 33-year-old Czech goalkeeper, who played a reduced role during the Blues' championship run last season, will not have to wait long for his reunion with his former club though.
Cech is expected to start in goal for the Gunners, last year's FA Cup winners, when they take on the Blues in the FA Community Shield match on Aug 2 at Wembley Stadium.
Here's a look at the five other players who have swopped colours.
1. Bill Dickson (left Chelsea in October 1953)
The Northern Ireland international defender spent six years at Chelsea, before Arsenal manager Tom Whittaker paid £15,000 (S$32,000) to sign the accomplished wing-half.
Injuries, however, plagued his stay at Highbury, and Dickson made just 31 starts, scoring once, in his three years in North London.
In 1956 and at the age of 33 with his career winding down, he left the First Division to join third-tier club Mansfield Town.
2. George Graham (left in September 1966)
A prolific scorer during his two years at Chelsea, where he scored 35 times in 72 appearances and won the League Cup in 1965, the Scot nevertheless had a strained relationship with Blues boss Tommy Docherty.
Repeated clashes between the two led to Graham's exit the following year, with Chelsea receiving £75,000 and Tommy Baldwin as part of the deal.
Graham would prove to be a success with the Gunners, both as a player and later as a manager in the 1980s and 1990s. He was Arsenal's top scorer in his first two seasons at Highbury, and would help them win the European Fairs Cup in 1970 and the League-FA Cup double in 1971.
He returned to manage Arsenal in 1986 and led the club to six major trophies in eight seasons.
3. William Gallas (left in September 2006, part-exchange in Ashley Cole deal)
It took 40 years before another player swopped Chelsea for Arsenal and the transfer itself that eventually brought the Frenchman to North London was incredibly protracted. The deal had begun 18 months earlier with Cole, then an Arsenal player, agitating to leave for Stamford Bridge.
Cole was not the only one to depart acrimoniously. Gallas, who won two league titles across five seasons with Chelsea, was also involved in several verbal spats with the Blues before he left.
He was later appointed captain by Arsene Wenger, but his time at the Emirates was less successful than in West London. He failed to win any silverware in four years at Arsenal and was stripped of the armband during the 2008/09 season after criticising teammates in a media interview.
4. Lassana Diarra (left in August 2007)
He was named Chelsea's Young Player of the Year in the 2005/2006 season, and started in their 2-1 win over Arsenal in the 2007 League Cup final.
However, the versatile Frenchman left just six months later, in search of more regular football as he struggled to nail down a first-team role.
His stay at Arsenal was short-lived though, as Diarra again saw limited action with the emergence of defensive midfielder Mathieu Flamini in Arsene Wenger's side.
He lasted just five months at the Emirates before a £5.5 million deal in January 2008 took him to Portsmouth, where he would win the FA Cup before Real Madrid splashed £19 million to take him to Spain.
5. Yossi Benayoun (left in August 2011, loan deal)
A silky and creative force for West Ham and Liverpool, Benayoun completed a £5.5 million transfer to Chelsea but his first season at the Bridge was ruined thanks to a ruptured achilles that saw him ruled out for more than six months.
His troubles continued with the arrival of Juan Mata the following year, and Benayoun was pushed further down the pecking order.
In a bid to revive his career, he joined Arsenal on loan for the 2011/2012 campaign and scored six goals in 25 appearances.
He even captained the Gunners in a League Cup match and scored in the final league game to help Arsenal finish third and deny North London rivals Tottenham Hotspur the final spot in the following year's Champions League.
