Demba Ba signed on 4 January 2013 for an undisclosed fee.
The Senegal international moved to Stamford Bridge following an 18-month spell with Newcastle United, and signed a three-and-a-half-year contract with the Blues.
Most comfortable playing as a lone striker, Ba's predatory instincts in and around the penalty area make him a difficult player to handle and he also possesses the ability to score spectacular goals.
He was eligible to play in the FA Cup and Capital One Cup in his first season here, but could not play for us in the Europa League having appeared in the competition for Newcastle. Ba made his Chelsea debut in an FA Cup third round tie away at Southampton, and it proved an introduction to remember as he scored twice in a 5-1 win for the Blues.
He scored his first home goal for the club 11 days later in a Premier League game against the same opposition, opening the scoring in a 2-2 draw. Ba suffered a broken nose on his return to St James' Park as the Blues fell to a 3-2 defeat in February.
It was a solitary Ba goal which secured our place in the FA Cup semi-finals, when a well-taken volley helped us overcome Manchester United in a sixth-round replay.
He was on target again at Wembley, but unfortunately his goal couldn't prevent us from falling to a 2-1 defeat at the hands of Manchester City.
Ba has featured sparingly during the current season, but his professionalism and desire certainly cannot be called into question, and he continues to pop up with vital goals when he does play, including a brace in the 4-0 win over Tottenham in March.
Born in Sevres, in the suburbs of Paris, Ba's career began at Port Autonome du Havre, where he played for two years between 1998 and 2000, before moving to Frileuse.
After a short spell with the French club, Ba, who started out playing in the centre of midfield but moved up front at the age of 18, transferred to Montrouge in 2001.
It was there he began to make a name for himself, and he then headed to England where he was offered trials with Barnsley and Watford.
Having enjoyed a fruitful relationship with former Chelsea player Ray Lewington, who was Watford manager at the time, it looked as though Ba had found a place to settle.
However, when Lewington left soon after, Ba moved back to France where he signed a one-year deal with Rouen in the Third Division.
A return of seven goals in 32 matches earned him a move to Mouscron, in the Belgian top flight, where an impressive albeit short spell paved the way for his transfer to 1899 Hoffenheim in the German Second Division at the beginning of the 2007/08 campaign.
It was to prove a significant time in Ba's development, and he was a key figure in helping the club gain promotion to the Bundesliga.
Their first season back in the top flight saw Hoffenheim finish in a respectable seventh, aided in no small part by Ba's 14 goals.
In January 2011, he was back in England, and signed for West Ham United.
After making his bow for the Hammers as a substitute in a game against Birmingham City, Ba endeared himself to the supporters a week later on his full debut, where his two goals helped West Ham fight back from 3-0 down to earn a 3-3 draw away at West Bromwich Albion.
On a personal level, his time at Upton Park went well, with seven goals in 12 appearances, but collectively the team underperformed resulting in their relegation from the Barclays Premier League, prompting Ba's move to Newcastle United.
The 27-year-old enjoyed a memorable time on Tyneside, where his ruthlessness in front of goal played a major part in their fifth-placed league finish in 2011/12.
He netted two hat-tricks in quick succession, against Blackburn Rovers and Stoke City, at the beginning of that season.
This impressive start to life at St James's Park was rewarded with the Premier League Player of the Month award in December 2011, and he finished the season as the club's top scorer with 16 goals to his name.
The 2012/13 campaign saw Ba continue where he left off, as he broke the deadlock with a fantastic volley against Tottenham Hotspur on the opening day of the season, while shortly after his brace at Goodison Park helped Alan Pardew's men secure a well-earned 2-2 draw against Everton.
His last performance in a Newcastle shirt came in their final game of 2012, a 7-3 defeat against Arsenal at the Emirates where he netted a brace.
Ba has established himself as a regular in the Senegal international set-up since scoring on his debut back in 2007 in an Africa Cup of Nations qualifier against Tanzania, though he has found himself out of favour of late.
He is the first Senegalese player to join Chelsea.