thumbails in similar threads

[Jonatthu]

It was close thanks a lot but...

I did that and happened this.

if($thread['fid'] == 4){
     $xtimgsimilar_thread = 'http://img.youtube.com/vi/'.$similar_thread['vidid'].'/mqdefault.jpg';
}

URL= http://img.youtube.com/vi/http://www.you...http://img.youtube.com/vi/http://www.youtube.com/watch?v=uuZE_IRwLNI/mqd

Just the url is wrong I need only the ID of the video "uuZE_IRwLNI"