Streep, 60, and Bullock, 45, hammed it up on stage trading mock insults before "making-up" with a full-on kiss at the Critics' Choice Movie Awards at Hollywood Palladium in Los Angeles. The two shared the prize for Best Actress.
Streep said she loved playing Julia Child in Julie & Julia.
"I'm really, really thrilled because I really love what I do," she said. "I love to work, and I love food and I love sex. And so did Julia Child. So it wasn't that much of a stretch."
Bullock, who won for her performance in The Blind Side, said she hadn't prepared a speech, but she used her time at the microphone to honour her fellow actresses and call for compassion for people who are suffering, a welcome allusion to the Haitian crisis.
"We're all so lucky to be here tonight when so many others are in pain," she said. "I hope we can all send good love and thoughts and whatever we can."
Other honours went to Mo'Nique, who was named best supporting actress for her visceral portrayal of an abusive mother in Precious; Saoirse Ronan, who won best young actress for her work in The Lovely Bones; and The Hangover was voted best comedy.
Intriguingly Nine, which came into the contest tied with Inglourious Basterds with a leading 10 nominations, ended up without a prize.
The Critics' awards are seen as a strong indicator for the Globes, which will be hosted by The Office star, comedian Ricky Gervais.
Gervais has promised some "gentle ribbing", principally aimed at "anyone younger and thinner and richer and more attractive than me".
"I can't wait to see Ricky Gervais do his thing. He was such a great choice to host that show. It's a rough crowd, everyone's at big tables talking to each other the whole night and drinking. It's pretty raucous," said Neil Patrick Harris, a Globe nominee. "I think they chose the perfect guy to host it. He'll be masterful in his lion tamer's skills."