Novak Djokovic says his decision to appoint former rival Andy Murray as his coach was "a surprise to everyone" but is "exciting for tennis".
Britain's three-time Grand Slam champion Murray, who retired from tennis in August, will work with Djokovic in the off-season and in the build-up to the Australian Open.
Men's record 24-time major winner Djokovic, speaking to Sky Sports, admitted his phonecall caught Murray "a little off-guard".
But the Serb, 37 - the same age as Murray - said the pair "connected really fast" and Murray took only a few days to agree to the role, less than four months after ending his career at the Paris Olympics.