Manchester City captain Vincent Kompany took to Twitter to congratulate fellow countryman Marouane Fellaini after the midfielder sealed a £27.5million move to Manchester United.
The move means Fellaini and Kompany now represent rival teams in the Premier League.
Despite the rivalry, Kompany found time to praise Fellaini after United confirmed the signing of the Belgium star from Everton.
Kompany wrote on his official Twitter account: "Congratulations @fellainiM! Any countryman doing well, I'm happy for. So now we will be neighbours. Careful I can be quite noisy."
Kompany, who picked up an injury against Newcastle in Manchester City's league opener, is likely to miss City's upcoming derby with United at the Etihad Stadium on September 22.
However the duo are likely to go head-to-head when United host their arch-rivals on March 1.
Meanwhile, Kompany will be hoping Fellaini is on form for Belgium's World Cup qualifying match against Scotland at Hampden Park on Friday.
Belgium are currently top of their European qualification group - three points ahead of Group A rivals Croatia.