Tony Bennett has been secretly managing Alzheimer's for 4 years, showing symptoms in rehearsals with Lady Gaga

• Tony Bennett was diagnosed with Alzheimer's disease in 2016, his family recently revealed.
• The 94-year-old singer's cognitive decline was noticeable in his latest recording sessions with Lady Gaga.
• Bennett is managing his condition by eating a Mediterranean diet and exercising three times a week.

Legendary singer Tony Bennett has been battling Alzheimer's disease for four years, according to a recent feature in AARP magazine.

The 94-year-old singer's family confirmed that he was officially diagnosed with the neurodegenerative disorder in 2016, but Bennett continued performing through March 2020.

"Both Susan and Danny said that backstage, Tony could seem utterly mystified about his whereabouts. But the moment he heard the announcer's voice boom 'Ladies and gentlemen - Tony Bennett!' he would transform himself into performance mode, stride out into the spotlight, smiling and acknowledging the audience's applause," wrote John Colapinto, the author of the AARP article.

Read more: 19 science-backed ways to reduce your risk of Alzheimer's disease, from reading to playing chess

Bennett showed signs of cognitive decline in recording sessions with Lady Gaga

The first signs of trouble came in 2015, when the "Way You Look Tonight" singer struggled to remember fellow musicians' names.

Bennett's symptoms of memory loss and confusion have worsened since then, and were evident in unreleased footage of recording sessions with Lady Gaga, according to AARP.

"The pain and sadness in Gaga's face is clear at such moments -- but never more so than in an extraordinarily moving sequence in which Tony (a man she calls 'an incredible mentor, and friend, and father figure') sings a solo passage of a love song. Gaga looks on, from behind her mic, her smile breaking into a quiver, her eyes brimming, before she puts her hands over her face and sobs," Colapinto wrote for AARP.

Gaga and Bennett recorded a follow-up to their album "Cheek to Cheek" between 2018 and early 2020. The collaboration is scheduled to be released this spring.

The singer is managing the disease with a Mediterranean diet and exercise

Susan Bennett, the singer's third wife and main caregiver, has been keeping him on the Mediterranean diet and a three-days-a-week exercise regimen, she told AARP.

The Mediterranean diet consists of vegetables, fruit, whole grains, legumes, fish, and olive oil; the eating plan has been found to reduce the risk of heart disease and stroke, and it may also benefit brain health.

Read more: How to kickstart healthy eating with this 1-week Mediterranean diet meal plan recommended by a registered dietitian

One small study published in 2018 found that people who followed the Mediterranean diet could delay the onset of Alzheimer's by up to 3.5 years, compared to those who ate a Western diet.

Bennett's fitness routine includes upper-body exercises with resistance bands, some light jogging, and squats and step-ups for his lower body, AARP reported.