In what circumstances can the C# 'is' keyword throw an exception?

I stumbled upon something like the following in our code base...

    protected bool IsThing(object item)
    {
        try
        {
            return item is Thing;
        }
        catch (Exception)
        {
            return false;
        }
    }

I'm trying to work out if there is any circumstance in which this catch will ever be visited?