The 24-year-old French-born attacking midfielder has agreed an $8.7m (£5.1m) deal with a $67m (£40m) buy-out clause.
The Ivory Coast international, a free agent after leaving Galatasaray, left Stamford Bridge in 2012 after scoring the winning penalty in the Champions League final against Bayern Munich.
SATURDAY'S MATCHES
• Botswana vs Guinea-Bissau 2:0
• Uganda vs Mauritania 2:0
• Sierra Leone vs Seychelles 2:0
SUNDAY'S MATCHES
• Lesotho vs Kenya 1:0
• Tanzania vs Mozambique 2:2
• Congo Brazzaville vs Rwanda 2:0
• Benin vs Malawi 1:0
Gourcuff was last coach of Lorient, leaving the job in May at the end of the Ligue 1 season. He has also coached at Le Mans and Stade Rennes and had a one-year spell in Saudi Arabia.
2nd round - fixtures & results
SATURDAY (19th July 2014)
• Botswana vs Guinea-Bissau 2:0
• Uganda vs Mauritania 2:0
• Sierra Leone vs Seychelles 2:0
The Super Eagles climbed three places in the Confederation of African Football region and 10 spots on the global list - up to 34th in the world.
The 27-year-old centre-back was part of the Desert Foxes squad that reached the last 16 of the World Cup in Brazil - their best performance at a finals.
The Baggies announced the arrival of the 25-year-old Dynamo Kiev player on Friday, saying they had broken the club's record.
SATURDAY
• Botswana vs Guinea-Bissau
• Uganda vs Mauritania
• Sierra Leone vs Seychelles
SUNDAY
• Lesotho vs Kenya
• Tanzania vs Mozambique
• Congo Brazzaville vs Rwanda
• Benin vs Malawi
Ba joined the Blues from Premier League rivals Newcastle in January 2013 on a three-and-a-half year deal for an undisclosed fee.
Cameroon vs Serbia 3:3
FACTS
Goals Cameroon
Castelletto (29'minutes), Aboubakar (63'minutes), Choupo-Moting (66'minutes)
Assists
Castelletto (63'minutes), Aboubakar (66'minutes)
..
Goals Serbia
Pavlovic (45'+1minutes), S. Milinkovic-Savic (45'+3minutes), Mitrovic (53'minutes)
Assists
Tadic (45'+1minutes), Zivkovic (45'+3minutes, 53'minutes)
Cameroon
Serbia