Sundress and tank top season is just around the corner, and what better way to complement your warm-weather look than with a polished updo like Dianna Agron's? Sp we went straight to the source to get the complete how-to from her hairstylist Matthew Monzon, who has also worked with Amy Poehler and Elizabeth Banks. "We decided together that we wanted something simple and chic," he says. A bone-straight texture was key in creating the effect, so Monzon began by applying John Frieda's Luxurious Blow Out Spray ($9; ulta.com) to Agron's damp hair before blowing it dry with a paddle brush. "It helped to get that smooth, sleek finish," he adds. After forming a deep side part on the left, Monzon created a low ponytail that sat at the nape of the star's neck. He split the ponytail into two sections, twisted each into a braid, then wrapped the plaits around the base of the style. A few spritzes of John Freida Crystal Clear Hairspray ($6; ulta.com) held the look in place.