Jennifer Lopez's famously rounded derriére actually Shrinking?

Her rounded derriére helped her to superstardom, but it seems Jennifer Lopez may have a little less of it these days.

After months of strenuous exercise as she prepared for a triathlon, Lopez's famous curves now seem distinctly smaller.

Last night the new mother-of-two showed off her firm bottom in a white figure-hugging dress at the Dolce & Gabbana fashion show in Milan.

Jennifer Lopez flaunts her derrière at the Dolce & Gabbana fashion show in Milan Fashion Week last night, but has it shrunk since this photo was taken in 2003?

Remarkably, the actress has regained her pre-pregnancy figure just seven months after giving birth to twins, thanks to her heavy work out schedule in preparation for the sporting event.

She took part in a charity triathlon in Malibu, California, earlier this month to raise thousands for the Children's Hospital Los Angeles.

Lopez was joined at last night's Italian event by her husband Marc Anthony and her Wedding Planner co-star Matthew McConaughey and his girlfriend Camila Alves.

Matthew McConaughey and his girlfriend Camila Alves pose with Lopez and Marc Anthony at the fashion event

The two couples, who have both become first-time parents this year, posed side-by-side on the red carpet.

Among the other celebrities admiring the Dolce & Gabbana Women's Spring/Summer 2009 fashion collection were burlesque star Dita Von Teese, supermodel Eva Herzigova and Adrien Brody's Spanish model/actress girlfriend Elsa Pataky.

The three women appeared to have coordinated their wardrobes beforehand, each looking like they'd comfortable fit in at a 1930s society hunting event.

Three's company: Dita Von Teese, Spanish actress Elsa Pataky and Eva Herzigova look like they're attending a 1930s society hunt

Glowing: Jennifer Lopez, Eva Herzigova and Claudia Schiffer strike a pose