Simple .htaccess question

Hello

Would anyone be able to help with this small problem...

I have 2 domains, www.example.co.uk and www.example.com

They are configured by my host to share the same webspace

What I would like however, is to use .htaccess to redirect a visitor who accesses the site via www.example.com to be redirected to www.example.co.uk

I somehow need to add this into my existing .htaccess code which redirects a non-www domain to a www domain for SEO purposes

Does anyone know how this may work?

In summary -

2 domains pointing to the same shared directory.

The .com domain (both http://www.example.com and http://example.com) need to redirect to www.example.co.uk

The .co.uk (http://example.co.uk) must also redirect to the www version (http://www.example.co.uk)

The code I currently have is below (this redirects non-www to www):

RewriteEngine On

RewriteBase /

RewriteCond %{HTTP_HOST} ^example.co.uk [NC]

RewriteRule ^(.*)$ http://www.example.co.uk/$1 [L,R=301]

Any suggestions welcome 

Change

^example.co.uk

(which only continues if the hostname is "example.co.uk")

to

!^www.example.co.uk

(which continues if the hostname is not "www.example.co.uk").

Thanks requinix - that works perfectly