Felicity Blunt works at a London literary agency.
Tucci's wife died of cancer two years ago. They have three children together.
"Stanley is very happy with her," a source close to the couple told UsMagazine.com.
"Emily loved Stanley on the set of 'Devil,' and just thought they would hit it off, so she set them up," the insider added. "It hasn't been easy for him getting into a new relationship, but Felicity is a lovely person and very warm and comforting."
The celebrity news Web site did not say if a wedding date has been set.