It seems that Roger Federer is serious about starting a boy band, tweeting "No seriously, we're actually starting a boy band." He joined Tommy Haas and Grigor Dimitrov (with David Foster on piano) for a second installment of Chicago’s “Hard to Say I’m Sorry.”

Their latest performance included a lot of improvements from their first show in January, including doing away with cell phone lyrics, harmonizing perfectly, adding some professional sound enhancements, and throwing in surprise guest Novak Djokovic.

The men sounded noticeably better than their first performance, proving practice (and teamwork) makes perfect. Who knows what’s in store next for the One-Handed Backhand Boys, but the world can't wait to find out.