Amanda Seyfried Helps Launch U.S. Open at USTA Opening Night Gala 2015!

Amanda Seyfried is all smiles while striking a pose at the 2015 Annual USTA Opening Night Gala held at the USTA Billie Jean King National Tennis Center on Monday (August 31) in New York City.

The 29-year-old actress was joined at the event by Anna Chlumsky, Kelly Rowland, Rosie Perez, Martha Stewart, Josh Groban, Lena Hall, Vanessa Williams, Alec Baldwin and his wife Hilaria.

PHOTOS: Check out the latest pics of Amanda Seyfried

“Singing with one of the best people I know! Thank you for having me @joshgroban #USOpen2015 #alliaskofyou,” Lena tweeted after performing a duet with Josh at the opening ceremony.

“You crushed it!!! A huge honor for me all around,” Josh added. “Thanks for joining.”

30+ pictures inside of Amanda Seyfried and others at the USTA Opening Night Gala…