Creating Formal Wear

Creating Formal Wear

Hello there! My name is Zayna. If you’ve been around the Ellie and Mac Facebook group, I’m probably not a stranger to you. If you are a stranger, it’s wonderful to meet you! I’ve been sewing since I was around 5 years old and I discovered Ellie and Mac almost 4 years ago. I struggled with ADHD for many years and one of those difficulties was with traditional sewing patterns. I’d get overwhelmed easily and it held back my sewing in a lot of ways. With the ease of Ellie and Mac patterns, both from the clear instructions and layer features as well as the inclusive size range, my spark was rekindled and I have been unstoppable in sewing a closet full of amazing clothes ever since…but there’s one thing I recently realized I was lacking. 

Special occasion dresses! With prom season upon us I’ve been deep diving trending looks to help offer guidance and suggestions on patterns and styles. One particular thing stood out to me about some of this year’s biggest formal wear trends (square neck corset back dresses, deep plunging halters, etc.)…you could hack a lot of them using the Oasis swimsuit as a base. I often see people on the quest for special occasion ideas in sewing since formal wear can be expensive, difficult to fit and not the most size inclusive, so I’m here today to help you with a little dress code decode on using the Oasis swimsuit to create a semi-formal and black tie look. 


Now for pattern options I actually did not hack these patterns to be for wovens I’m using formal knit fabrics. I selected a few to play with and decided on this black stretch knit satin and a glittered Fukuro double knit. In my quest I found tons of amazing options including holographic fabrics, velvet, sequined knits, and textured stretch mesh that would all make amazing formal wear.

Semi-formal apparel can be defined as dressier than you’d wear within a professional setting but not as formal as an evening gown or tuxedo. For the semi-formal look we’re going to mash the Oasis swimsuits’ square-neck and tie back option with the Trendsetter skirt to make a fun and on-trend LBD (Little Black Dress). 


From the Oasis Swimsuit you will want to grab the pattern here Oasis Swimsuit Pattern and need the following pattern pieces:

  • Front Bodice (labeled for Styles 1 & 2): cut 1 liner, cut 1 main

  • Back Bodice Style 2: cut 1 liner, cut 1 main

  • Bikini Back Loops Style 2: cut 2 main

  • 2 straps (cut lengths located on front bodice pattern piece)

  • Front binding (cut lengths located on front bodice pattern piece)

From the Trendsetter skirt which can be found here Trendsetter Skirt Pattern  and you will need the following pattern pieces:

  • Skirt Front: cut 1 main

  • Skirt Back: cut 1 main

  • Waist band (cut in half width-wise, will explain why further on!): cut 1 on fold

  • Pockets: cut 4 mirrored pieces, 2 sets


To keep this from boring you to sleep I’ll keep it simple and we will walk through primarily where this pattern gets hack-y. For the bodice you will construct the bodice following the exact instructions from the Oasis swimsuit pattern for Bodice Style 2. 

Once your bodice is constructed we’re going to take the halved waistband from the Trendsetter skirt, (your waist band should measure 3”x length based on your size) and we’re going to clip it to the bottom of the bodice, right sides together in place of the bodice waistband.

Next you’ll assemble your Trendsetter skirt according to the pattern instructions. Once you’ve reached the step where you’d take your gathered skirt and attach to the waistband you will clip or pin it to the bottom of the halved waistband, opposite the bodice, with right sides together and stitch it. 


From here you’re going to hem it, give it a good press and you’re good to go! One of the perks of using a bathing suit hack for formal wear is this dress gave me support and structure so I was able to forego a bra for this particular style. Give it a twirl and you’re good to go!


Black Tie is a term that when I see it on an invitation I go through a roller coaster of both excitement and stress…I love to dress up but sometimes dressing up can be quite the endeavor to get the look I’m hoping for. Black Tie dress code is typically defined by being a tuxedo or dark suit, elegant separates, formal evening gowns, or elevated cocktail attire. 

One of my favorite Black Tie trends is a dramatic plunging neckline with a high-slit skirt…the look that demands to be seen. For the Black Tie mash up we’re going to use the AMAZING textured glitter Fukuro double knit fabric. This time we’re going to mash the one-piece bodice from the Oasis swimsuit with the skirt from the Wrapped in Love dress to achieve the slit. I reused the waistband piece from the Trendsetter skirt since I already had it cut but you could just as easily create a waistband by cutting two 3” width strips by the length of .85 x your waist measurement (or 85%).


From the Oasis Swimsuit you will need the following:

  • Front Bodice Main: cut 4 outer, cut 4 liner (mirrored, 2 sets total)

  • Halter straps: cut 2 main

  • Back straps: cut 2 main

From the Wrapped in Love Dress which can be found here Wrapped in Love Dress you will need the following:

  • Skirt front: cut 2 mirrored 

  • Skirt back: cut 1 on fold

  • Pockets: cut 4 total (2 sets, mirrored)

Waistband, again can either be the piece we used above from the Trendsetter skirt or:

  • Cut two strips 3” x 0.85 times your waist measurement, of your main fabric


Once again here we’re going to construct the bodice following the instructions exactly as written from the Oasis swimsuit instructions. 

I overlapped the bodice 2” and basted it to ensure enough overlap while maintaining the plunge.

Next you’ll take your two waistband pieces and face them right sides together and we will be sandwiching the halter bodice between both waistbands, clipping thoroughly all the way around like so. Serge or sew the sandwiched waistband pieces ensuring you’re catching all of the layers as you go. Once completely sewn, flip the waistband pieces down.

Now construct your skirt following the pattern directions included in the Wrapped in Love Pattern. Once you reach the step to attach your gathered skirt, you are going to clip or pin it to the waistband. Your waistband pieces should be wrong sides together with the bodice encased on the opposite end, and we’re going to attach the skirt to the opposite raw edge. If using a heavy material I highly encourage adding a clear or ¼” elastic to support the skirt weight at this step. My skirt material didn’t pull too badly since the waistband was fairly structured so I didn’t personally include it in this make.

Once you attach the skirt you once again want to give it a good press, twirl around, and accessorize! Now for me I don’t typically wear a bra when swimming but I do for formal events so to ensure I got the support I wanted I did include a little breast tape and a backless bra in addition to using powermesh to line the bodice. For reference I have a bust size of US 40L. 

I hope you are feeling inspired by this hack and have some ideas for your next semi-formal or black tie event such as prom, wedding season, that big award at work (go you!), military ball…you name it! If you give it a try please share in the Ellie and Mac Facebook Group or feel free to tag me on Instagram @bluestockingsewing 

(Written by: Zayna Thomas)

PDF Sewing Patterns

Download your pattern immediately after your order.