Prince made a surprise appearance to congratulate Jay Z and Justin Timberlake on their “Legends of Summer” concerts at Yankee Stadium. His Purpleness was among the guests at a party at the Darby on Saturday night, following the sold-out shows. Guests included Beyoncé, Jessica Biel and Timbaland. A source told us, “Everyone arrived at around 12:30 a.m. and stayed till after 4 a.m. [Club owner] Richie Akiva popped over 30 bottles of Ace of Spades champagne and 15 bottles of 901 tequila.” Incidentally, a song on Jay’s new album, “Beach Is Better,” includes the lyrics, “Started at the Darby; Ended up at 1Oak; Left the house with 100 grand; Ended up near broke.”