Mary-Kate and Ashley Olsen are about to come out of a tube.

According to Fashion Wire Daily, the two 17-year-olds (who are heavy into merchandising) are teaming up with Aquafresh toothpaste, pitching a new flavor that will feature their faces on the product along with the slogan, "It's How You Smile."

Because the toothpaste is to appeal to children, the photo of the twins on the package will be from when they were 13, the news service reports. The twins' toothpaste is to hit stores in September.

This also is the first time a children's toothpaste is being co-branded with live celebrities rather than the usual animated characters.

Robert Thorne, CEO (and co-founder along with Mary-Kate and Ashley) of Dualstar -- the twins' consumer-product company whose retail sales are expected to top $1 billion this year -- said in a statement: "Mary-Kate and Ashley are closely involved in the development of all of their products.

"They personally selected the flavor for the mary-kateandashley brand toothpaste and their picture for the packaging of the toothpaste," he said.

Ashley added, "Now kids can grow up with us, and learn to have fun brushing."