Berlin  - After a rediscovery by the likes of Justin Timberlake and Pete Doherty, hats have become the official fashion accessory of today's youth. It's hard to avoid young men making old- style hats seem fresh and trendy.

There's no denying the new trend. Hendrik Schaulin, a stylist from Hamburg, explains: "The older generation make a point of being leisurely and progressive. To set themselves apart, the younger generation has had to adopt more dapper styles."

Hats can work as easily for British pop artists and skaters or men in polo shirts.

"If you style a hat properly, even people in jogging suits can look good."

The key is to make sure that the hairstyle, face and hat all work together, he says.

"People with longer faces who wear hats should wear something that seems to shorten the face," advises Marion Feldmann of Otto. "To make a round face look oval, people should wear hats that appear to stretch out the face."

Experts agree that the trilby is the most popular hat nowadays.

"This is a hat with a small brim, usually with a wide band," says Bernhard Roetzel, a Berlin style adviser. He says hats as a style statement marks a return to the 1960s and 70s.

"You look back at the styles from back then and play with replacement pieces from today."

Some common trends set hats apart nowadays. Unlike your grandfather's hats, they are not stiff. They also fit the head better.

Alongside the trilby, other hats enjoying a resurgence include the pork pie, the panama, the derby and the top hat.

Catarina Midby, a spokeswoman for H&M's design division, also says hats are an important accessory for young fashion. "The great thing about hats is that you can combine them with almost anything. They go as well with a suit as they do with a simple jeans and T-shirt outfit."

Midby says "woollen felt gangster hats" and straw hats are currently fashionable. Feldmann says big floppy hats from the flower- power days with wide brims and bright colours should be part of any hat collection, alongside a classic, tough leather cowboy hat.

The especially brave can try out checkered hats or bright accessories. Appliques are a serious theme this year for both Feldmann and Midby. If that's too much, Roetzel suggests straw hats with a brightly coloured band. Hats in classical colours can help keep a modern outfit grounded. Men can't go wrong with colours like chocolate brown, grey, white or black and white contrasts.

Hats can easily become everyday wear. "From a fashion history perspective, hats are suitable for all occasions," says Feldmann. Nonetheless, she urges hat wearers to observe social conventions.

Schaulin agrees. "You should take your hat off indoors, even if you are young."

But Roetzel says different rules apply for the young. "You should take your headgear off in church. Otherwise, you should keep it on, just like sunglasses. The hat is simply a part of your styling."

Experts are still undecided on whether girls should participate in the hat's comeback. "For the time being, it's predominantly men who are wearing hats. But we'll have to see if the trend carries over to women," says Midby.

Roetzel says he sees no problem if fashion adventurers want to pep up women's outfits with a man's hat. People should simply experiment.

INFO-BOX: The right hat for summer and winter

Hats are not just a winter accessory. When picking a summer hat, stylist Hendrik Schaulin advises paying close attention to the material. Warmer months are best served with straw hats, like the Panama. They breathe and keep the heat off. But woollen trilbys are also a good choice. Hats of darker cotton or felt are recommended for the winter.

INFO-BOX: How to style your hat

If you want to wear a hat like a celebrity with stalking groupies, you should complement it with oversized sunglasses, advises style advisor Bernhard Roetzel. If that's too glamorous, just pull the brim deep down in front and let some hair peek out the sides. In general, your hat should go with your hairstyle. If you have long bangs, your hat should tilt backwards. If you have a shorter haircut, your hat should sit low on your head. (dpa)