'Cats' Musical Wiki

This page is part of the Costume Workshop series. This tutorial assumes a basic knowledge of sewing techniques, and use of a sewing machine with at least a zigzag stitch, if not a dedicated stretch stitch or overlocker.

Materials and Tools[]

  • 2 metres / 2 1/2 yards good quality Swimsuit Spandex - min. 8% spandex fibres, ideally with nylon rather than cotton or polyester.
  • 10x snap fastenings (sew on or clamp) OR 10x hook and eyes
  • Thread to match your fabric
  • Sewing machine with stretch stitch - dotted zigzag and false overlock ideally, zigzag minimum
  • (optional) Overlocker
  • Fabric marker - air or water soluble ink pen.

Altering a Commercial Pattern[]

There are numerous "Catsuit" / "Unitard" patterns available commercially, however none combine the features of having a single seam at the centre back, and shoulder fastenings.

Below is a diagram to demonstrate how to alter a commercial two piece (front seam) unitard pattern to be a single back seam. It relies on the stretch in the spandex to twist around the waist and allow the waist reduction to be pulled in at the back seam.

Sizing - as a general rule of thumb, it is recommended to cut spandex 10% smaller than your measurements - ie. a 30" waist should be cut to 27". Therefore, on the fold should be 13 1/2".

Costume Uni alt

For people with a significant Bust to Waist ratio, it's not possible to get an exact fit just from reducing at the centre back. If this is the case, then side darts are added running from the armhole to hip, set several inches back from the true side seam. This is best done in a fitting.

To alter the shoulder seams into fastenings, it is recommended to add extra layers of fabric: facings and plackets to strengthen the opening, which needs to pass over the model's hips and chest. Either cut extra inches onto the pattern to allow a larger hem and overlap, or add a facing to the front, and a placket (extended flap to tuck under) on the back. Overlap the front over the back for a neater finished look.

A crotch gusset is rather tricky to insert, but adds to the comfort and security of the wearer as it greatly reduces the chance of the crotch seam splitting. The gusset is either an elongated diamond or triangle shape, with the short width running from the front of the inner leg seam to the centre back seam, and the length running along the inner leg seam.

Cutting List[]

  • 1x Body
  • 2x Sleeves
  • 2x facings for shoulder fastenings
  • 2x plackets for shoulder fastenings
  • 1x crotch gusset (Optional)

To Make Up[]

First, sew up the centre back seam. If adding a crotch gusset, do so by sewing it to the front of the inner leg seam. Then edge the stirrup, and sew up the inner leg seams in one long line. Sew up the sleeves. Add the facings/plackets or hem the shoulder openings, and hem the front and back neck. To insert the sleeves, it is helpful to pin or tack the shoulder fastenings closed, and sew over the very last 1/2" in the seam allowance, to produce a full arm hole in which to insert the sleeve. Ease in the sleeves. Hem arms and legs. Finally, add the snaps or hooks and eyes to the shoulder fastenings.

As mentioned before, in fitting consider if side seam darts will tighten the under-bust fit, also at the collar it is often helpful to add a horizontal dart about 2" below the neck that can give the appearance of the collar being a separate piece.

It is recommended to wash your completed unitard before painting and especially before dyeing, as the fabric will have been treated with sizeing prior to sale. An unpainted unitard is machine washable at cold or warm cycles. However bleach must NEVER be used with spandex - the bleach will destroy the stretch fibres. Retain fabric scraps, and wash and dye with the unitard, to keep as paint practice pieces and future repair patches.