Beyoncé and Blue Ivy make surprise appearances at Jay-Z's Reasonable Doubt 30th-anniversary show

E! News reports Beyoncé joined Jay-Z onstage at his July 10 Yankee Stadium concert celebrating 30 years of Reasonable Doubt, duetting on 'Can't Knock the Hustle' and performing 'Love on Top.' Daughter Blue Ivy Carter contributed a piano solo during 'Feelin' It,' and the family moments drew some of the night's loudest cheers.