Desperate Housewives star Eva Longoria has shared how her sister and mother led her on the path to becoming McDonald’s McHappy Day ambassador.

Ms Longoria told Deborah Knight she’s been a “long-time fan” of Ronald McDonald House Charities, having grown up with an older sister with a mental disability.

“[Lisa’s] just the kindest, sweetest woman, who has really taught me a lot about compassion.

“I was kind of born into her world, and born into a very, very giving family.

“We knew about volunteerism very early on in our lives, thanks to my mum who always made us give back and participate in the community.

“All of this work that I continue to do is just an extension of … my family’s work.”

In addition to buying a Big Mac, $2 from which is donated, customers can also support RMHC by purchasing a helping hand or pair of silly socks.

“You can do so little and help so many.”

Press PLAY below to hear the full interview

McDonald’s is an advertiser with 2GB and 4BC.