Quick sewing question

[soloula]

I'm making DD1 (5yo) a child and wearing outside in October-appropriate version of this costume for Halloween. I've bought stretchy silver sequin jersey material to do the neck and cuffs etc but I'm not sure what I should use to make the neck cuff piece sit right as it's a very drapey fabric. Should I use interfacing? If so, what type. If not, then what? I'm a novice and a teeny bit out my depth but hoping with the help of mumsnet and YouTube I can muddle something that looks like a Starfire costume.

I think for handiness sake, I would get a pale coloured polo neck top or jumper and tack it on by hand. If you use intrefacing it won't stretch enough to get on without an opening at the back. The sleeves will be a pain to fit properly and probably keep falling down on their own but attached to a top underneath they will stay put. Bonus points for keeping her warm with the jumper!

Thanks Rafferty. I'm planning on making it more an all in one dress so she can layer up underneath. Should maybe have said that before - sorry! So cuffs and belt will be sewn onto the dress. I was thinking of maybe having a stand alone collar (maybe without the high neck for ease). Maybe fixing it with Velcro or poppers at the back but it's the stiffness that I'm wondering about.

Do you mean the bit sitting across the chest?
Tere are different types of interface.
You could make the collar bit but as you mention leave an opening at the back for velcro which might work.
Or cut two pieces of the same material, sew them together. that might stabilize the fabric.
Make sure you rae using zig zag stitch.
Not sure if any of that is a proper solution for you

Use iron on interfacing.
And if the sequins are glued on put a layer of waxed paper between the fabric and your sewing machine.
Glue really buggers up sewing machines.