To get this heart you'll need to return to the Hall of Heroes.  Go to the pool in the middle and jump onto the middle torch.  It will blast you to a ledge near the ceiling.  Move around the ledge until you reach the misty portal that will transport you into a tapestry.

Once in the tapestry, jump up the levels until you reach the head and grab the prize.  Continue hopping to the right to drop out of the tapestry.  Exit the hall and continue until you reach the area where you found the soccer goal.  You'll find a lava icon on the ground - step on it to be transformed.

Once transformed, making a straight run back towards the Hall of Heroes.  When you reach it don't go in, but look for a heart nearby locked in a cage.  While transformed you can destroy the cage and take the heart.  If you run out of time, return to the lava icon and try again.