Alex Rodrigo Dias da Costa, better known as Alex (born 17 June 1982 in Niterói), is a Brazilian footballer who plays for Paris Saint-Germain F.C. and the Brazil national football team. He is known for his ability to score goals with his strong foot and his strength. Having been bought by the Premier League club Chelsea in 2004, he was loaned to Dutch team PSV and he won 3 Eredivisie titles with them. Alex finally joined the Chelsea squad in the summer of 2007 after three years in the Netherlands.

Santos
Alex began his career with Santos of Brazil, making his first team debut in 2002 which he later then became part of the pillars of the team. Alex made his professional league debut in the 1-1 draw against Fluminense. He was signed by English club Chelsea in 2004 on the recommendation of famed PSV and Chelsea scout Piet de Visser, but because of potential problems in attaining a work permit, he was loaned out to Dutch club PSV.

PSV (loan)
The joint contract of Chelsea and PSV loaned Alex to PSV for three years, with Chelsea having a €1 million buy-out clause. Alex eventually played three years at PSV, donning the number 4 jersey for the Dutch club. While playing for PSV, he earned himself the nickname "The Tank" due to his cannonball-like free kicks and his strong physical stature. He formally joined PSV in the 2004–05 season, helping the club win a domestic double of both the Dutch Eredivisie championship and Dutch Cup that year. Alex won a second straight Dutch league championship in the 2005–06 season with PSV. Alex stayed a third season at PSV on loan in 2006–07. However, he was later injured and played no part in PSV's UEFA Champions League quarter-final against Liverpool, which PSV lost 4–0 on aggregate.

Chelsea
Alex was granted a work permit on 2 August 2007, and completed his transfer to Chelsea after agreeing personal terms and passing a medical and signing a three year deal. On 14 August 2007, Alex was presented to the English media, in a press conference with manager José Mourinho, and was given shirt number 33. He made his debut on 19 August 2007 when he came on as a substitute for Florent Malouda against Liverpool in the 85th minute.

Alex enjoyed his longest spell in the first team during the 2008–09 season. On 13 October 2009, Alex signed a new four-year contract with Chelsea, keeping him at Stamford Bridge until the summer of 2013. In light of Ricardo Carvalho's departure to Real Madrid, Alex started the 2010/11 season as first choice centre back for Chelsea, alongside John Terry. In the summer transfer window, Alex was the subject of a bid from Premiership rivals Arsenal. On 3 December 2011, Alex submitted a transfer request, which was accepted. He had been the subject of a bid from Queens Park Rangers in the first transfer activity under their new manager Mark Hughes. However, the move was broken down after both parties reportedly failed to agree personal terms, QPR could not match his wage demands and Alex stated he did not want to stay in England.

Paris Saint-Germain
On 12 February 2012, Alex made his debut for PSG in a 0-0 draw against Nice. The following week on 19 February 2012, Alex scored a 30 yard screamer from a lay-off free kick, his first goal for Paris Saint-Germain against Montpellier. On November 6, 2012, Champion League, Paris Saint-Germain vs Dinamo Zagreb, Alex score the first goal, whose fantastic half-volley evaded the reach of Ivan Kelava after 16 minutes. On 27 January 2012, Alex joined Paris Saint-Germain for £4.2m to reunite with his former manager Carlo Ancelotti.