The rehearsal dinner began as an American custom, a meal for the wedding party after the ceremony had been walked through, and it has travelled. At a destination wedding it has usually become a welcome dinner for every guest who has arrived: the first evening on which the two families and their friends are in the same place. That change is what makes the question of what to wear to a rehearsal dinner harder than it looks. It is no longer a private supper. It is the opening night of a three-day event, and it has its own unwritten rules.

The first rule is one of proportion. The dinner should be dressed one step below the wedding itself, never level with it and never a preview of it. If tomorrow is black tie, tonight is a good shirt and trousers, with a jacket to hand. If tomorrow is a linen suit on a beach, tonight is a linen shirt on a terrace. The invitation generally says something, in words such as "island chic" or "smart casual", and where it says nothing it is entirely proper to ask the couple or whoever is organising. The outfit chosen for the wedding stays in the wardrobe, pressed, until it is needed.

The second rule concerns colour, and it applies mainly to women. Convention leaves white, ivory and cream to the bride for the whole of the celebration, and many brides wear white on this evening as well as the next. A guest avoids the question by choosing colour. The Amelia linen dress shirt is worn on its own as a dress, and in Dubarry, Violet, Hibiscus or Coral Orange it sits at the right level for a welcome dinner in a warm place: evidently chosen, not competing. It is one of the garments in the women's linen collection, alongside the PP linen blouse, which in Orchid works with a long skirt or wide trousers of her own for a more formal table.

For men the range is narrower and the decisions are about sleeve and trouser. A long sleeve reads as an evening shirt in a way a short one does not: the Bliss Linen Shirt in Vanille or Dark Blue, cuffs fastened at the start and rolled once the toasts are over. The Monte-Carlo Male in Oyster, with its walnut buttons, is the other evening shirt in the collection. PP Trousers 100% Linen in White are appropriate for a man in most summer settings, and PP Casual Linen Trousers in Sapphire Blue or Oatmeal where white feels like too much. Shorts are for the beach party the day after. A PP blazer in natural fabrics, carried and not necessarily worn, settles any doubt about the host's expectations. The shirts and trousers are in the men's linen collection.

Whether linen belongs at an occasion like this is a fair question, and the answer is yes, with one condition. Linen is entirely at home at a wedding in a warm climate, as can you wear linen to a wedding sets out, provided it arrives looking cared for. A shirt that has crossed a continent folded in a suitcase needs ten minutes of attention before it is seen by a room of relatives. Hang it in the bathroom while the shower runs, or use the steamer most hotels will send up, as described in can you steam linen. Linen will crease again during the evening; that is accepted. Starting creased is not.

The setting decides the rest, and it is usually one of four. On a beach, the ground is sand and shoes may be left at the edge of it, so trousers should be of a length that can be turned up once without looking improvised. In a vineyard or a garden, the ground is grass or gravel, and a narrow heel or a thin leather sole will suffer. In a courtyard or on a town terrace, stone holds the day's heat until late and a long sleeve is no burden. On a boat, the host's instructions about footwear take precedence over everything else. Certified Belgian linen is suited to all four because it is comfortable through a long evening that begins in sun and ends in a breeze.

It is also an evening of standing, and of being photographed. There are drinks before the meal and speeches after it, and the pictures taken tonight are often the candid ones that families keep. Two practical points follow. Pockets should be empty and collars checked before the first toast. And it often turns cooler at the coast late in the evening: a second layer, whether a jacket for him or a wrap for her, is used more often than people expect.

Members of the wedding party should take their lead from the couple, who may want the families coordinated or simply comfortable. Everyone else can rely on the old principle. Be a little more dressed than the place requires and a little less than tomorrow will, and let the evening be about the two people it was arranged for.

What to Wear to a Luxury Wedding  ·  What to Wear to a Beach Wedding  ·  The Linen Shirt for a Wedding Guest