Gray, the filmmaker behind sports movies such as Miracle, The Rookie and Million Dollar Arm, and his wife Kristen, launched the Charlotte + Gwenyth Gray Foundation in June (15) in support of their girls, four-year-old Charlotte and two-year-old Gwyneth, who are battling Batten disease.

The fatal neurodegenerative condition is so rare there is little funding for research or clinical trials to find a cure or treatment, so the Grays decided to set up their own foundation with a goal of raising $10 million (£6.25 million).

Celebrities including Julianne Moore, Jennifer Garner, Channing Tatum, Jessica Alba and Jessica Biel helped to raise awareness about the cause by posting notes about it on social media, and now Hathaway has stepped up her involvement by taking the issue to TV.

During an appearance on U.S. breakfast show Good Morning America on Wednesday (23Sep15), the Les Miserables star showed off a pin promoting the foundation and urged viewers to give what they can to kickstart medical trials.

She explained, "The pin that I'm wearing is in honour of Charlotte and Gwenyth Gray, two little girls who have been diagnosed with Batten disease...

"Their parents are trying to raise money to find a cure for them. They're $2 million into their goal of $10 million, but they need another $2 million for them (experts) to start doing clinical trials, so if you have a dollar to spare, please, please, please (donate), these little girls' lives depend on it.

"The life expectancy of children with Batten disease is between six and 12. Charlotte's already four so time is of the essence."