You will need a 39 inch (99 cm) long size US 8 (5 mm) circular needle.

Although it’s knitted entirely in simple stockinette stitch, this jacket is constructed in an unusual way. The back and sleeves are knitted conventionally, but the fronts are knitted sideways, so the ruffle “grows” out from the front edges.

Source: Knitting in No Time by Melody Griffiths Page 88