Redirect a particular request to another domain?

we had sent out a news letter where a href tag that was supposed to go
to
another domain ended up looking like this:

http://www.ourdomain.com/www.theirdomain.com

Is there an easy way in nginx to redirect this type of request to the
www.theirdomain.com website? or maybe I should just create a file with
the "
www.theirdomain.com" name and do a meta tag refresh on it?

thanks!