Zakuani has been selected for the tournament in South Africa despite earning his last, and only, cap for his country seven years ago.
The 26-year-old central defender has recently broken back into the Peterborough first team after a long stint on the substitutes' bench and was instrumental as Posh upset the odds to win at Championship leaders Cardiff last weekend.
Zakuani said on Twitter: "Even Disney couldn't write the last 10 days of my life WOW!
"First I force my way back in (to the starting XI) and put on a good performance, beat the league leaders the next game, then hear my brave sister beats cancer!
"Gets even better, my brother is visiting me this weekend, and THE ZAK is back in the Congo squad! Called up and I can't stop grinning!
"DR Congo manager watched me in the last two games and is buzzing. Glad he took the time, now let's win the African Nations. Hopefully I can join the squad late so I don't miss too many Posh matches."
Congo begin their African Nations Cup campaign against Ghana on January 20 before facing Niger (January 24) and Mali (January 28).