The 38-year-old actress hit the red carpet on Sunday evening (January 5) at the Beverly Hilton Hotel in Beverly Hills, Calif.
She was also joined by her The Loudest Voice co-star Annabelle Wallis.
During the event, the series is up for Best Miniseries or Television Film.
The Golden Globes will be hosted by actor and comedian Ricky Gervais this year, marking his fifth time as host. Make sure to tune in at 8pm ET/5pm PT on NBC.
FYI: Sienna is wearing Gucci with Forevermark jewelry. Annabelle is wearing a Zuhair Murad gown and Cartier jewelry.