Rosamund Pike's Mini Bun This modern bun shows how Rosamund Pike kept her sleek, straight bob looking supersharp: she had an undercut. The shorter hairs at the neck remove bulk at the back and also make it easier to create a bun like this without flyaways. If you have very thick hair, consider this cut to keep your look sharp whether you wear it up or down! Image Source: Getty / Kevork Djansezian