Lady Gaga looked stunning as usual as she attended Sinatra 100: An All-Star Grammy Concert celebrating Frank Sinatra's 100 birthday in Las Vegas. Gaga was accompanied by her father Joe Germanotta and her friend Tony Bennett. At the end of the event, Mother Monster closed the show with her rendition of 'New York, New York' dressed with a black suit by Brandon Maxwell. Take a look at the full peformance in HD as well as professional photos below.