HELPING HAITI: Mick Jagger, L’Wren Scott, Rachel Weisz, Catherine Zeta-Jones and a bevy of other notables will host next month’s Rx Haiti benefit and auction to help provide prosthetics for earthquake victims. Michelle Williams, Sienna Miller, Jude Law, Helmut Lang, Zac Posen and Edie Falco are some of the others rounding up friends for the May 6 event at The Greenhouse, the rooftop garden at Scholastic’s SoHo offices. After seeing firsthand the lack of adequate medical care while pitching in with the relief effort earlier this year, David Colbert, a Manhattan-based internist and dermatologist, decided to try to do something about it. Items up for bid will include pieces from Thakoon, Narciso Rodriguez, Calvin Klein, Fred Leighton and Diana Broussard; photography from Annie Leibovitz, EJ Camp, Sante D’Orazio and Jim Marshall, and art from Elizabeth Peyton, Shawn Dulaney, Rachel Harrison and Chris Martin, among others.