Japan's Kei Nishikori has signed up former French Open champion Michael Chang as his coach from next year.
The 41-year-old American is expected to act as an advisory coach to the world No 17 with full-time coach Dante Bottini remaining in his current role.
Chang is known for his tenacious baseline defence and two-handed backhand shots and became the youngest-ever male winner of a Grand Slam when he triumphed at Roland Garros in 1989 at the age of 17.
"Excited to announce an addition to the team. Michael Chang will join us in 2014," Nishikori, who will be 24 on December 29, said on Twitter and Facebook.
Chang will accompany Nishikori to 'some' ATP tournaments and 'advise him in the run-up' to Grand Slam events, according to his agent, IMG Japan.
Named the 2008 ATP Newcomer of the Year, Nishikori reached the quarter-finals of the 2012 Australian Open. His world ranking hit a career-high 11th in June this year.