The 'Mamma Mia' actress - who married sculptor Don Gummer in 1978 - has developed a soft spot for the 'Anchorman' star, 47, after watching his comedies and even prefers him to 34-year-old Hollywood heartthrob Ryan Gosling, who she claims is too young for her.
She told W magazine: "The movie that makes me cry is 'Anchorman'. I have the biggest crush on Will Ferrell. I love him in every film he does.
"I mean, Ryan Gosling could be my child. I'm not going to have a crush on a child. Will Ferrell is a man."
The 65-year-old Oscar-winner - whose latest film, 'Into The Woods', is set for release on Friday (09.01.15) - isn't the only cast member to have developed an interesting celebrity crush.
Her co-star Emily Blunt - who has 10-month-old daughter Hazel with husband John Krasinski - admitted she finds actor Roy Scheider and his smoking habit attractive in the iconic 1975 shark attack flick 'Jaws'.
Emily, 31, said of the late star, who died in February 2008, aged 75: "I have a crush on Roy Scheider in Jaws. It's the way that cigarette dangles out the side of his mouth.
"No one smokes a cigarette like him."