The 33-year-old actor was single since splitting with his girlfriend of nearly five years, reported Us magazine.
Pakzad has been spotted with the "Pineapple Express" actor recently, including accompanying him to the IndieWire Honors event in West Hollywood.
"Isabel hugged Dave and hung out with him for a while and they seemed chummy, very close. (When James received his award) Isabel got a huge smile on her face.
"She cocked her head to get a better viewpoint and applauded a lot during his speech and giggled at his jokes. She had a huge grin on her face and seemed absolutely smitten with him," a source said.