Hollywood veteran Betty White has jokingly claimed that the secret to a long and healthy life is to “avoid anything green,” as she prepares to celebrate her 100th birthday.

The Golden Girls actress will reach the milestone age on January 17 and said she feels “lucky”.

“I’m so lucky to be in such good health and feel so good at this age. It’s amazing,” she told People magazine.

Accrediting her good health partly down to her diet, she explained: “I try to avoid anything green, I think it’s working.”

The Proposal star also thinks having a positive outlook is key, telling the publication that she was “born a cockeyed optimist”.

“I got it from my mom, and that never changed. I always find the positive,” she added.

This isn’t the first time that she has stressed the importance of “enjoying life,” previously telling Parade: “Accentuate the positive, not the negative. It sounds so trite, but a lot of people will pick out something to complain about, rather than say: ‘Hey, that was great!’ It’s not hard to find great stuff if you look.”