my $thing = OverloadingClass->new();
my $subref = overload::Method($thing, 'eq');

##</code><code>##

package MyOverLoaded;
use overload
    'eq' => \&my_equal;

# just an example overloaded implementation of eq
sub my_equal {
    my $self = shift;
    my $comparator = shift;
    return length($$self) == length($comparator);
}

sub new {
    my $class = shift;
    my $thing = shift;
    bless(\$thing, $class);
}

package OverLoadedSubClass;
use base qw(MyOverLoaded);

package main;
use Devel::Peek qw(CvGV);

my $thing = OverLoadedSubClass->new("It's my birthday!");
my $sub   = overload::Method($thing, 'eq');
print CvGV($sub); # prints "*MyOverLoaded::my_equal"