Cruise theme party nights have replaced formal nights on many Australian ships. This leaves many wondering what to wear to a Gatsby Party, White Party, Nero (the all-black equivalent on New Zealand cruises), or Back to School Party.

Bianco, P&O's White Party

This all-white event is usually the biggest themed party night on any P&O cruise. Everyone dresses in white, often adding 'bianco' accessories such as hats, sunglasses, jewellery or feather boas.

In line with P&O's smart-casual evening dress code, you can spice up your white T-shirt poolside outfit into something more exotic. For men, a white shirt with a pair of white jeans or shorts will fit the theme with little effort. For a more cruisey feel, an unbuttoned white shirt with a white vest or T-shirt underneath would also work. Don't forget to bring your white fedoras and caps, too.

For the ladies, keep it easy with a white summer dress and sandals, or white jeans and top. White shorts are also OK, but you may want to glam it up with an elegant top so it doesn't look like you've come straight from the pool.

Bianco's only requirement is that you dress in all-white-everything, so rock up in your nicest white garments and dress to impress on this night to remember. Don't stress too much if you forget anything for this event, as P&O offer accessories for most themed events on board.

Get ready to bust a move on the specially made dance floor, which is raised slightly above the pool deck, and enjoy a white cocktail or check out the white selfie wall leaving you with lasting memories of the night. Kids and adults are both welcome to this event, so make sure you pack enough white for the entire family.

Gatsby Party

A trickier question is what to wear to a Gatsby Party on a P&O cruise. This dress code is almost formal, with plenty of men in vintage suits and women in glamorous flapper dresses and fancy headpieces.

This high-end cocktail party requires a little more attention to capture the Gatsby essence and complement the jazz music and Champagne. For men, a white long-sleeve shirt with braces or suspenders, suit pants and a bow tie is a classic option. Hat styles include a flat cap such as the newsboy or cabbie; a fedora or Panama hat; a straw boater or bowler hat.

Ladies can bring out the sparkly dresses with long black gloves, or keep it casual in a little black dress with heels. Whatever you chose to wear, jewels in your hair or a headpiece are a must. P&O does offer 1920s-style accessories for the Gatsby evening if you do leave something at home, or feel unprepared on the night.

In the lead-up to the big night, P&O's daily program includes onboard '20s dance lessons (free) and workshops to make a Gatsby-style headpiece adorned with feathers, lace and sequins ($12).

Back To School Party

P&O's back-to-school-themed event, offered on cruises five nights or longer, will set your inner child free. This adults-only event is sure to have you dancing along to bangers from your high school days, so dress up as your 18-year-old self or favourite teacher from high school. Costumes aren't a must, but if you can still fit into that Year 12 uniform, why not show it off? Accessories can include glow sticks, backpacks, headbands, ribbons in your hair or anything else reminiscent of your days as a student.

Nero Party

P&O's Nero or Black Party was inspired by the Bianco White Party, but tailored for New Zealand cruises to celebrate one of the country's national colours. Wearing your All Blacks rugby gear is totally acceptable or just pack your best black clothes, including black suits for the guys or black dresses for the girls. Spice it up with a black hat, sunglasses, jewellery or a wig.