Defender Nathaniel Clyne joined Crystal Palace on a short-term agreement after leaving Selhurst Park eight years ago.
Right-back, who had been training with the team after being released by Liverpool, made 137 appearances between 2008 and 2012 for the Eagles.
“I’m a London boy, this is where I grew up. I’m back home and all my family and friends are here,” he told cpfc.co.uk.
“It’s surreal being back, enjoying it and hopefully I can just crack on and enjoy my football again.”
Clyne made 14 international appearances and earned his first England call-up under current Palace manager Roy Hodgson.
Chairman Steve Parish said: “Nathaniel is a fantastic character to have around this squad and we are delighted to secure his services for the upcoming period.”
“He is a first-rate professional, just as he was when I first met him more than a decade ago. His presence and experience will be invaluable.”