Streep graced the stage at the 25th annual film event in California to accept the second ever Icon Award in recognition of her outstanding movie career.
She told the crowd, "I feel like I'm an example now in my dotage that you can't put those old gals out to pasture - we've got a lot to say."
She follows the award's first winner Michael Douglas, who was presented with the prize in 2011.
Roberts, who plays Streep's daughter in the Oscar-tipped movie, was handed the Spotlight Award, and she thanked the actors and crews she has worked with over the years for helping boost her performances.
She said, "I learned in high school ... It is a scientific fact that all birds fly finer and faster in formation than any bird that flies alone."
The Pretty Woman actress also presented the Chairman's Award to Tom Hanks. Other recipients included Sandra Bullock, who won the Desert Palm Achievement Award, Actress for her performance in space thriller Gravity, and Bruce Dern, who walked away with male equivalent of the same prize for his turn in father-and-son movie Nebraska.
12 Years a Slave director Steve MCQueen was honoured with the director of the year award, while Mandela: Long Walk to Freedom stars Idris Elba and Naomie Harris presented rockers U2 with the Sonny Bono Visionary Award for their "unparalleled humanitarian work against extreme poverty, disease, and social injustice".
The film festival runs until 13 January (14).