The 25-year-old winger can play on either flank, with his qualities of speed and finesse a regular problem for opposing defences.
Born in Lisbon on September 26, 1983, Ricardo Andrade Quaresma Bernardo began his career with local club Sporting, making his debut as a 17-year-old.
While at Sporting, he worked his way into the first team and became a regular during the championship-winning 2001/02 season alongside Cristiano Ronaldo.
He made 59 league appearances in two seasons, scoring eight goals, before Barcelona approached for his services in the summer of 2003, paying six million Euros to secure his signature.
Quaresma's form in the 2005/06, 2006/07 and 2007/08 campaigns helped seal a succession of league championships, and regular Champions League football.
He is no stranger to Stamford Bridge, having played four times as a Porto player against the Blues, twice in 2004/05 and twice again two years later.
Quaresma becomes our first and only signing of the winter transfer window, and will stay with us until the end of the season.