"Are you pregnant?" Leno replied.
"Yes, I am," she said.
Driver said she loves being pregnant but is frequently sick.
"I don't know why they call it morning sickness," she said. "I am sick morning, noon and night, but it's a fair trade-off."
Driver didn't reveal the name of the father.
She would not be releasing additional details and had no other statement, publicist Jessica Kolstad said Friday.
Driver stars on the FX cable TV series "The Riches," which premieres Tuesday.