10/08/2013 AT 12:00 PM EDT
As Forrest Gump, Tom Hanks
famously declared, "Life is like a box of chocolates." Only now it looks like he has to be extra-cautious about what sweets he pulls out of that box.
The affable two-time Oscar-winner, 57, revealed while appearing on The Late Show with David Letterman
Monday night that he has been diagnosed with Type 2 diabetes
, although he called the condition "controllable."
"I went to the doctor, and he said, 'You know those high blood sugar numbers you've been dealing with since you were 36? Well, you've graduated! You've got Type 2 diabetes, young man,' " Hanks told Letterman
Hanks stopped by the show to promote Captain Phillips
and looked significantly slimmer than he appears in the film, in which he plays the heroic real-life ship captain
who dealt with Somali pirates who invaded his vessel.
Letterman wasted no time in complimenting the grandfather
. "You look wonderful, you look like a kid for God's sakes!"
"I'm maintaining the temple," Hanks replied in good humor before launching into the diagnosis and later downplaying its severity.
"It's controllable," he said. "Something's going to kill us all, Dave."
Letterman, 66, who underwent quintuple bypass surgery
in 2000, also revealed that he too suffers from high blood sugar and also had to go on a special diet.
Hanks, who joins the ranks of celebrities including Paula Deen
, Drew Carey
and Randy Jackson
, who have made their Type 2 diabetes diagnoses public, also said that watching his weight is key to his health – even if he can't entirely abide by his doctor's orders.
"My doctor said, 'Look, if you can weigh as much as you weighed in high school you will essentially be perfectly healthy and not have Type 2 diabetes.' and I said to her, 'Well, I'm going to have Type 2 diabetes,' " he said with a laugh.
"I weighed 96 pounds in high school," he explained. "I was a very skinny boy!"