
I’ve never seen this show, but this kid looks like he’s got some serious swag!
So it looks like he’s got a bit that fits over his nose, the monocle itself, and a string with a little triangle bit hanging off the end.
The easiest way I can see to do it and still have it stay on your face without adhesive is to find yourself a pair of costume coke-bottle framed glasses, also called nerd glasses at some costume shops. Harry Potter glasses will work too. The color doesn’t matter, but make sure you something cheap since you’ll be modifying them and you don’t want to be out too much money if you mess up.
What you’re going to want to do is very carefully cut away the left lens and frame of the glasses, leaving the bridge intact. Sand down the sawed off edge of the nose bridge so it doesn’t poke you when you wear it. If the glasses you got are a color other than white, either pop out or cover the lens so you can paint the monocle white. Make sure you use a sealant over the paint after it dries so it doesn’t rub off on your face when you sweat.
For the hanging bit, I would suggest using a length of white satin cord (though white hand embroidery floss can be used too since it’s easier to find, or white twine, or even white electrical wire from Radio Shack! It’s up to you, really) You can simply tie it around the remaining temple of the modified glasses near the lens and encase it in a bit of model magic.
Let me pause here for a second and say how much I love model magic. It’s super light weight, it’s easy to mold, and it’s cheap! It also has a bit of give even after it dries so it’s hard to break. Just make sure you have a bit of water around to smooth the surface when you join to pieces. It does also have the tendency to crack as it dries but if you keep an eye on it and fill gaps as they appear, it’s totally ideal for small bits of projects like this. Alternatively, though, you could use blue/yellow epoxy sculpting putty, commonly known as green stuff. It’s stronger, and it doesn’t crack as it dries, but it’s more expensive.
Anyway, once the encased bit is dry, I would reinforce it with a dot of hot glue or superglue just so it doesn’t slide around on the glasses. Then use your remaining model magic or green stuff and sculpt triangle at the bottom of the cord. I recommend sculpting it around the cord and letting it dry that way then reinforcing with a dot of glue, but it’s also possible to simply sculpt the piece and glue it on after. I just don’t think it’ll look as nice. Once that’s done, if the triangle isn’t the right color, paint it and seal it like you did the glasses. If it is, still paint the design on it and seal it.
Hope that was helpful and hope your 21st is an awesome one!