The actress' parents were in the audience as she belted out the Star Spangled Banner at the rally in Charlotte, North Carolina.
She took to Twitter.com to post live updates and urge followers to cast their votes at the November (12) presidential elections, writing, "Singing the National Anthem for the opening of the Democratic Convention! Couldn't be more excited! Exercise your rights as citizens and vote! Vote! Vote!"
The highlight of the evening was an appearance by First Lady Michelle Obama, who gave a heartfelt speech backing her husband, U.S. President Barack Obama, for another term in the White House.
She won over a host of famous faces, with Riley writing, "My First Lady is first class all the way. That speech was inspiring. She is everything I aspire to be," and Cher echoing, "Just watched Michelle Obama speak & am completely overwhelmed! She was amazing! She is truly a 'First Lady'! A woman to admire & emulate!" while Jamie Foxx added, "Tears in my eyes... Michelle Obama, true angel.... God bless America."
Entourage star Adrian Grenier wrote, "We are so lucky to have a First Lady such as Michelle Obama, she inspires me; a nation's mom with solid value," while Dirty Dancing actress Jennifer Grey told fans, "I love Mrs. Obama!!! Michelle Obama wrote her own gorgeous speech," and singer Ricky Martin gushed, "Such a beautiful and powerful speech!!! Real! Honest! Emotional! Passionate! Thank you First Lady Michelle Obama."
Mia Farrow adds, "I knew tonight would be great but it was spectacular and unforgettable."