Kids nowadays seem to grow up so fast -- and two of Genoa City's littlest residents are not immune. The show has released a casting call that will "age" two of its younger characters into their mid-teens.

According to the casting call, Y&R is seeking 18-year-old performers to play the roles of Summer Newman and Fenmore Baldwin. Both of the characters will be appear as 15- or 16-year-olds on the show's canvas

Summer was born on-screen on December 18, 2006. The character is now described as "fun" and "feisty" and otherwise a "typical teen."

Fen born on-screen on October 13, 2006. Three years later, the character was "aged" to be about six years old. Fen will return to Genoa City from boarding school and "adjustment will be an issue."

Earlier this year, The Young and the Restless aged another character, Kyle Abbott. The character, last seen in 2011 as a ten-year-old, will now appear as a 20something.

The recast Summer and Fen are expected to appear just in time for the summer teen storylines.

UPDATE: Newcomer Max Ehrich has been cast as Fen. He will first appear on June 11.

Lindsay Bushman has been cast as the now-teenage Summer Newman. Bushman appeared as a young Kate on General Hospital. She'll make her Y&R debut on June 8.