The 43-year-old Oscar-winning actress was spotted kissing Doyle at LAX airport and sources say the couple, who went to college together, are smitten with each other, reported Us magazine.
"They went to college together. It's going really well," a source said.
Doyle previously dated Crowe for two years after meeting on tour while he was her guitarist.
Zellweger's last serious relationship was with actor Bradley Cooper, but they split in March 2011, as she wanted marriage while he did not.
The actress was previously married to country singer Kenny Chesney, while Cooper was once wed to actress Jennifer Esposito.