Lyndsy Marie Fonseca is an American actress known for playing Colleen Carlton on the CBS daytime soap opera The Young and The Restless, Dylan Mayfair on the ABC series Desperate Housewives, and Ted Mosby's daughter on How I Met Your Mother. She also played Katie Deauxma in the 2010 superhero film Kick-Ass. She is currently starring as Alex in the CW's action series Nikita.