VIDEO: Roger Federer, Tommy Haas and Grigor Dimitrov team up for another musical performance

https://twitter.com/rogerfederer/status/842807550223548416 Roger Federer is taking his vocal skills a little too seriously. During the Australian Open, his ‘boy band’ consisting of Grigor Dimitrov, Tommy Haas and himself teamed up with David Foster(Haas’s father in law) for a rendition of the…