There's a 71-year-old guy in Scotland named Bill Duncan who was diagnosed with dementia in 2011. And he's gone downhill since then.
Most of his memories have faded over the past few years. And in the last 12 months, he's forgotten his whole history with his wife, Anne.
He didn't remember they were married. But he still liked being with her a lot, and thought she was really pretty.
So a few weeks ago, he asked if she'd MARRY him.
Anne says he started to get "very amorous" with her, and kept telling her how much he liked her. So she agreed.
Their friends and family loved the idea, and they had their wedding in the backyard. They even danced to the same song they danced to the first time.
Anne says they have good days and bad days now. But despite it all, he's still the same man she fell in love with.