Ashley Cole has signed for Derby as a free agent on a deal until the end of the season.
The 38-year-old defender - and three-time Premier League winner - has been without a club since leaving LA Galaxy in November and will now play under former Chelsea and England team-mate Frank Lampard.
Considered a part of England's 'Golden Generation', Cole racked up 107 international caps as well as 682 club appearances for Arsenal, Crystal Palace (loan), Chelsea, Roma and LA Galaxy.
Cole told RamsTV on Monday: "I had a conversation with Frank, maybe a month, two months ago. (It was) general chitchat about how good the team is playing. He said 'Would you be interested in coming here?'
"For me it was a no-brainer. Of course I kept in touch with Lamps, saw how well the team has been playing and followed Derby since he got here. It was a no-brainer to come here and get involved in this great environment. Hopefully we can push for promotion [to the Premier League]."
Derby boss Lampard added: "I'm delighted that we've been able to secure Ashley's services for the rest of the season.
"He's a fantastic player, a quality left-back, and he also brings great experience to the dressing room.
"I know him very well from our time together at Chelsea, and with England, and I also know what he can bring to the group and the influence he will have.
"Ashley is in good shape, which doesn't surprise me because he's an excellent professional, and he will compete for a place in the side like every other player here.
"I've made my feelings known over the last couple of days just how highly I think of Ashley and I have no doubt whatsoever he will be a positive addition to our squad."
Derby are currently sixth in the Sky Bet Championship and return to league action against Preston on February 1 after their FA Cup fourth-round trip to Accrington Stanley on Saturday.