Yes, use the same yarn, and sew the edges together lining up the rows as you go. Do it loosley to give it the same stretch as the rest of the cap.

Did you see my answer to you regarding the thread size in your other post about the size being WAY off? Just curious if that was why the hat turned out so small.

-Babka

If it's gathered on top I would do exactly that. Thread the tail on a needle and run it through the all the top stitches and pull it tight, adjust the gathers and then sew it together

Thanks everyone. Babka, I used just what the pattern called for on the hook and the yarn and yes, big stitches and thick yarn. I did have to increase the stitches and used about 35 instead of 29. Finished it last night and it is just the cutest thing. Added just a few more stitches seemed to give it more give.