When Whitney Houston delivers her greatest hits package in May, the collection will boast a bit of help from Enrique Iglesias, Deborah Cox, and Q-Tip, among others... not that she needs it.The head of Houston's record label, Clive Davis, told MTV News that the venerable diva's upcoming greatest hits collection will carry her 1999 duet with Iglesias as well as a new duet with Canadian R&B songbird Deborah Cox. Houston's collaboration with Iglesias, "Could I Have This Kiss Forever," turned up on the Latin singer's "Enrique" album last year. The Houston collection will also carry a new track written for the singer by Q-Tip and Raphael Saadiq. The release would be Houston's first since 1998's "My Love Is Your Love," which has sold more than 2.5 million copies since its release in November of that year. It would also mark Houston's first greatest hits offering.