An upper may include a first knitted portion configured to form an outer surface of the upper, a second knitted portion configured to form an inner surface of the upper, where the second knitted portion is at least partially coextensive with the first knitted portion, an interstitial space between the first knitted portion and the second knitted portion, and a knitted connection structure connecting the first knitted portion to the second knitted portion. The knitted connection structure may extend at least partially along at least one of a tongue and a collar of the upper, and the second knitted portion may include at least one double jersey knit structure that is coextensive with the first knitted portion.