Chelsea have reported entered the race to sign highly-rated Porto defender Eder Militao.
The 20-year-old only arrived at Porto during the summer, but he has quickly established himself in the first team at the Estadio do Dragao and his form is understood to have attracted interest from some of Europe's biggest clubs.
Manchester United, Juventus and Everton have all been credited with an interest in the centre-back ahead of the January transfer window.
Chelsea are known to be in the market for defensive reinforcements next month too, and the Daily Mail reports that they have now joined a growing list of potential suitors.
Militao is thought to have the same agent as Brazilian compatriots David Luiz and Willian, both of whom currently play for Chelsea.
Maurizio Sarri views Militao as a possible long-term replacement for captain Gary Cahill, who is expected to leave the club when his contract expires.
However, Porto are hoping to make a significant profit on any sale of the Brazil international and are understood to have placed a £44m price tag on his head.