Single sisters take wedding pics for dad with Alzheimer's

Unmarried twin siblings pose for very special photoshoot

The two women pictured here may look like happy brides, but neither of them is married – or even engaged.

See also: How to be a good friend to someone with Alzheimer's

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Sarah and Rebecca Duncan know that their father, who suffers with Alzheimer's disease, may not be around to see their wedding days, so took the unusual step of creating the heart-warming photos now.

According to ABC News, the 23-year-old twins from Texas wore donated wedding gowns and held bouquets for the photo shoot, which was taken in a neighbour's garden.

"We just randomly thought of this idea," Becca told ABC News. "Me and Sarah know that our dad is more than likely not going to be at our wedding -- it's not being a downer or anything; we're just being realistic -- so we decided to do these wedding pictures with Dad."

The girls said the professional photography session was "the best thing in the world".

"Seeing him coming down the hall and seeing us in our wedding dresses and him smiling. It meant so much to us," Becca said.

"It's something that we're going to have for the rest of our lives."

Mr Duncan, 80, has now reportedly been moved to a 24-hour nursing facility due to his failing health.