As one of the world's best known musicians Elton John can rely upon the support of a host of stars at his charity events. And this week was no exception, with soul singer Gladys Knight joining the Piano Man and his partner David Furnish for a gala evening in New York. The multi-award winning songstress, who teamed up with Elton in 1986 for charity single That's What Friends Are For, attended 'An Enduring Vision', the city's seventh annual benefit to raise funds for the Elton John AIDS Foundation. And the lucky guests, including Emily Mortimer and Delta Goodrem, were treated to a special duet by the two singers, which Georgia-born Gladys insisted they'd not practised together. "He called me and said, "Look, if were going to do something, we're just going to do it. You're a pro and I'm a pro.", she revealed. During the event - which included a cocktail reception, a dinner and live auction - actor Tim Allen was recognised for his contribution to the charity. The Santa Clause 3 star was quick to deflect credit back to his host, however, saying: "It’s a terrific thing that he's done and I'm just doing the best I can."