London - Roger Federer, still smarting from his Wimbledon humiliation, said Wednesday that he will play the Hamburg clay-court tournament from July 15.
"I am happy to let you know that I will also be playing #Hamburg this summer, where I have many fond memories," Federer tweeted.
The 31-year-old Federer had said on Tuesday that he would play the Gstaad clay-court event from July 22.
He has added the two events to his schedule as he looks to bounce back from his Wimbledon misery, where the seven-time champion lost in the second round to Ukraine's 116-ranked Sergiy Stakhovsky in what was his worst Grand Slam defeat for a decade.
The world No 3's choice of tournaments will surprise many in the sport with the US Open, played on hard courts, getting underway on August 26.
Federer won the first of his four Hamburg titles in 2002 but has not played in the German city since 2008.
His shock Wimbledon loss last week ended his run of 36 consecutive Grand Slam quarter-final appearances, having not gone out of a major before the last eight since the 2004 French Open.