Brazil centre-back Thiago Silva has signed for Chelsea on a one-year deal, with the option of another.
The 35-year-old has joined the Blues on a free transfer having left Paris St-Germain after their Champions League final defeat on 23 August.
He will bolster the Blues' defence, which conceded the most goals (54) in the Premier League top 10 in 2019-20.
"I am so happy to be joining Chelsea. I am delighted to be a part of Frank Lampard's exciting squad," Silva said.
"I'm here to challenge for honours and I look forward to playing at Stamford Bridge very soon."
Silva, who has made 88 international appearances, played more than 200 games for PSG during his eight years in the French capital, winning seven consecutive Ligue 1 titles.
He is manager Frank Lampard's fifth major summer signing, following former Nice defender Malang Sarr, England left-back Ben Chilwell from Leicester and forwards Hakim Ziyech and Timo Werner.
In the first window since the Blues' transfer ban was lifted, Chelsea have also been linked with 21-year-old Bayer Leverkusen and Germany winger Kai Havertz.
Chelsea begin their Premier League campaign away at Brighton on Monday, 14 September (20:00 BST).
Chelsea is a great club