Seydou Doumbia sealed his move to Roma after the Serie A club secured his services from CSKA Moscow 14.4 million euros.
Doumbia, who is currently at the African Nations Cup with Ivory Coast, signed a new contract until June 2019.
In November, Doumbia starred in a Champions League match at Manchester City, scoring both goals in CSKA's shock win.
The 27-year-old forward wrote a message to CSKA fans on Instagram:
Three things learned from Ivory Coast's Group D-clinching 1-0 triumph over Cameroon at the African Nations Cup.
Gradel comes to life
A frequently featured substitute of recent times, with former coaches Francois Zahoui and Sabri Lamouchi using him sparingly as cover for Gervinho and Salomon Kalou, Max Gradel has slowly come to life in this tournament, as some playing time for his country is proving what a useful player he can be.
Missing out in the first match against Guinea, spending the whole...
Max Gradel's stunning first-half strike saw Ivory Coast beat Cameroon 1-0 and finish top of a tightly-contested African Nations Cup Group D to qualify for the quarterfinals.
The former Leeds midfielder, who is now at St Etienne, launched a spectacular strike from outside of the area to beat Cameroon goalkeeper Fabrice Ondoa and put Ivory Coast ahead in the 35th minute.
Knowing they needed a goal to keep their hopes of progression alive, Cameroon were unable to find the target and instead exited...