The 10-year-old, whose parents are Reese Witherspoon and Ryan Phillippe, got what countless Twi-Hards can only hope for: A chance to meet Robert Pattinson.
Witherspoon, 34, who's working with the Twilight heartthrob on Water for Elephants, introduced her daughter to Pattinson, 24, Thursday on the movie's Piru, Calif., set.
"Ava seemed especially excited to meet him," an onlooker tells PEOPLE, who also notes that younger brother Deacon, 6, chatted with the British actor.
"The filming with Rob is going really well," adds an on-set source "and Reese was excited for the kids to meet him."
But Witherspoon isn't the only cool mom in Hollywood. Teri Hatcher recently helped her daughter meet another star who causes commotion wherever he goes – Justin Bieber.
Reporting by PERNILLA CEDENHEIM