James Purefoy lusted after Vanity Fair co-star Reese Witherspoon - even though they are both attached and the actress was pregnant.
The 40-year-old British thespian plays aristocrat Rawdon Crawley alongside Witherspoon's Becky Sharp in the period drama.
Purefoy, who is currently dating an unknown girlfriend, says: "It was impossible not to (fancy her). She's pretty, smart and has enormous grace and elegance.
"On the other hand, she's married and was pregnant during filming . But to daydream about? Why not?"
Witherspoon gave birth to Deacon, her second child with actor husband Ryan Phillippe, while the film was being shot in England in October 2003.