According to the New York Post, the actors have decided to give their relationship another chance, after a few years of not being together. The Bridget Jones Diary star and the Good Night, and Good Luck director dated before in 2001.
A source told the paper that the two stars enjoyed a romantic dinner on September 24 at the Tower Bar in Los Angeles.
According to witnesses, Zellwegger, 37, and Clooney, 45, "cuddled, held hands and then slow danced to the piano music".
Zellwegger was briefly married to country singer Kenny Chesney in 2005.