creating treeWidgetItem using emitted signal from thread class

hi

i m facing some problem when i m emitting signal from thread and connect the slot from other class...this slot will add every time new treeWidgetItem....but when thread class emit the signal ,it is adding second time 2 same treewidgetItem in treeWidget, third time 3 same treeWidgetItem and so on...

some part of the code is...

thread class.....
emit createLog();
Gui class
connect(&thread,SIGNAL(createLog()),this,SLOT(Crea teLogFile()));
///definitoion
void class::CreateLogFile()
{
QTreeWidgetItem *pItem = NULL;
pItem = new QTreeWidgetItem(treeWidget);
pItem->setText(0,"text");

///close

If anybody know this ...help me...