Magento 1.7 PHP – Fix ‘Call to a Member Function addAttributeToSelect() on a Non-Object’

I'm getting this error when trying to filter products by a custom attribute.

In magento i have setup my custom attribute as 'featured' with 'yes/no' choice. This attribute has then been assigned to all attribute sets and various products then set to yes on the featured value.

On my homepage (cms page) i am then loading my template as a block

{{block type="catalog/product_list" name="home.catalog.product.list" alias="products_homepage" category_id="45" column_count="4" template="catalog/product/homelist.phtml"}}

And my template code (homelist.phtml) consists of the following

<?php
    $_productCollection=$this->getLoadedProductCollection();
    $_helper = $this->helper('catalog/output');
?>
<?php if(!$_productCollection->count()): ?>
<p class="note-msg"><?php echo $this->__('There are no products matching the selection.') ?></p>
<?php else: ?>

<div class="category-products section group clearfix">
    <ul class="products-grid">
<?php // Grid Mode ?>

    <?php $_iterator = 0; ?>

<?php
    $_items = $_productCollection->getItems();
        $_items->addAttributeToSelect('featured');
        $_items->addFieldToFilter(array(
            array('attribute' => 'featured', 'eq' => true),
        ));
?>
<?php $_collectionSize = 5 ?>

    <?php $_columnCount = 5; ?>
    <?php $i=0; foreach ($_items as $_product): ?>
    <?php if ($i++%$_columnCount==0): ?>

    <?php endif ?>
            <li class="item<?php if(($i-1)%$_columnCount==0): ?> first alpha<?php elseif($i%$_columnCount==0): ?> last omega<?php endif; ?> col span_1_of_5">
                <a href="<?php echo $_product->getProductUrl() ?>" title="<?php echo $this->stripTags($this->getImageLabel($_product, 'small_image'), null, true) ?>" class="product-image"><img src="<?php echo $this->helper('catalog/image')->init($_product, 'small_image')->resize(135); ?>" width="135" height="135" alt="<?php echo $this->stripTags($this->getImageLabel($_product, 'small_image'), null, true) ?>" /></a>
                <h2 class="product-name"><a href="<?php echo $_product->getProductUrl() ?>" title="<?php echo $this->stripTags($_product->getName(), null, true) ?>"><?php echo $_helper->productAttribute($_product, $_product->getName(), 'name') ?></a></h2>

 <?php // echo $this->stripTags($this->helper('core/string')->truncate($_product->getDescription(),65,'...', $_remainder, false)) ?> 

 <?php echo $this->stripTags($this->helper('core/string')->truncate($_product->gets_desc(),200,'...', $_remainder, false)) ?> 

                <?php echo $this->getPriceHtml($_product, true) ?>

                <div class="actions">
                    <?php if($_product->isSaleable()): ?>
                        <button type="button" title="<?php echo $this->__('Add to Cart') ?>" class="button btn-cart" onclick="setLocation('<?php echo $this->getAddToCartUrl($_product) ?>')"><span><span><?php echo $this->__('Add to Cart') ?></span></span></button>
                    <?php else: ?>
                        <p class="availability out-of-stock"><span><?php echo $this->__('Out of stock') ?></span></p>
                    <?php endif; ?>

                </div>
            </li>

    <?php if ($i%$_columnCount==0 && $i!=$_collectionSize): ?>

    <?php endif ?>

    <?php if($i==5): ?>
        <?php break; ?>
    <?php endif; ?>
    <?php endforeach ?>

    <?php if ($i%$_columnCount==0): ?>

    <?php endif ?>


<?php endif; ?> 

</ul>

</div>
        <script type="text/javascript">decorateGeneric($$('ul.products-grid'), ['odd','even','first','last'])</script>