"It's a grown-up love story," she told The Associated Press Saturday in Davos, where she was attending the World Economic Forum's annual meeting, adding that she simply loves acting with Hoffman.
"Sometimes you just have a proper chemistry with some actors and I had it with Tony Hopkins and I have it with Dustin," she said.
The film, likely to be released later this year, isn't the first time the pair have worked together. The last time was the 2006 literature as reality film "Stranger Than Fiction," with Thompson playing a writer.
It's a role the British actress is familiar with, given that she received an Academy Award in 1996 for best adapted screenplay for her adaptation of Jane Austen's "Sense and Sensibility." Thompson also adapted author Christianna Brand's "Nurse Matilda" books into the 2005 film "Nanny McPhee."
The 1992 best actress Academy Award winner was drawn to the books and made the film because it provided her the opportunity to work on a movie that appealed to children and their families, too.
"I think there are very few good movies you can take everyone to," she said, adding that some were "either post-ironic" and went straight over the heads of children, denying them the chance to enjoy it.
"Children are very, very sensitive creatures and we owe them our best shot as actors and writers," said Thompson, who has completed the script for the second film in the "Nanny McPhee" trilogy, and has an 8-year-old daughter.
"It will be called 'Nanny McPhee UXB' which stands for unexploded bombs," she said, adding that shooting is expected to start this fall.
