I would like to add a label AFTER a group of radio inputs IF the first has a certain class

<label>Has the strategy and all of it's relevant background documents been uploaded</label>

<label for="Radio1"><input type="radio" name="uploaded" class="required cat1" id="Radio1">Yes</label>

<label for="Radio2"><input type="radio" name="uploaded" id="Radio2">No</label>

Radio1 has the class, but I'd like to insert a label after the last (in this case Radio2)

I thought I could use this:

$('input[type="radio"].cat1').siblings('input:last').after('<label>Hi!</label>');

But it doesn't work. Can you pick what I am doing wrong?