It was a Ralph & Russo Couture gown from the Spring 2014 collection for Sonam while on the Cannes 2015 red carpet. Diamond earrings and Chopard sapphire with a pair of Zanotti sandals added some more blue to the already blue gown.
The choice of color is great as the blue completely stood out against the red carpet, her hair looked great, the only disappointment was her eye make-up which made her look tired.
Overall Sonam did manage to look glamorous and classy, both at the same time.

at 68th Annual Cannes Film Festival

at 68th Annual Cannes Film Festival

at 68th Annual Cannes Film Festival
It is approved that, royal blue is an impressive and gorgeous color for party dress. http://www.aiven.co.uk/prom-dresses-c119/a/blue_tone_o48v1063/