Donna Mills does 100 sit-ups a day, plays tennis five times a week at 85 but won't quit Doritos

Donna Mills is keeping fans on their toes at 85, from launching an OnlyFans account to revealing the intense fitness routine she credits with keeping her active.

The former ballerina, best known for playing the scheming Abby Cunningham on "Knots Landing," revealed to Fox News Digital the demanding fitness routine she credits with keeping her moving — including 100 sit-ups, 50 leg lifts, up to an hour on the bike and, sometimes, tennis five days a week.

And while Mills has long been disciplined about her health ...