Hilary Swank partners with Iams to raise awareness for the Iams 'Home 4 the Holidays' pet adoption drive, held at Bideawee Animal Center. New York City, USA - 19.10.09

The Boys Don't Cry star was shooting in The Karoo, South Africa when she took a shine to a local stray who followed her around the set - and she decided to make sure she was OK before she left the country.

Convinced someone was looking after the dog - because she looked well fed, Swank was stunned when she learned the mutt was actually close to death.

She says, "I took her to the vet and the vet said..., 'She's actually fat because she's full of worms'.

"She had so many fleas on her they said that they should have sucked all her blood out; they couldn't believe it... She had seven ticks in one ear and six in the other.

"They said, 'If you don't take this dog, she will certainly not make it.'"

Swank took the dog home with her and added another rescued pet, Roomie, last year (08).

She adds, "They bring a lot of joy to my life."

The actress' love of strays will come into full effect this holiday season - she has signed on as a celebrity spokesperson for Iams Home For The Holidays campaign, and is urging potential pet owners to adopt animals this Christmas.

She explains, "There are eight million animals that need homes and about six million of them get put to sleep every year."

Source: WENN