Roger Federer has signed a three-year deal to play at his hometown event in Basel until the age of 38.
The 35-year-old, who missed the second half of last season with a knee injury, has committed to Swiss Indoors until 2019.
Federer, who returned to action in January, won his first Grand Slam title since 2012 and his 18th in total with victory in the Australian Open.
"Playing in Basle is always a highlight of the year," he said.
He has won Swiss Indoors seven times since making his debut in the tournament in 1998.