Create a referral URL

In addition to giving a friend a referral code, is it possible to have a URL that incorporates the Referral code?

I'm imagining that the URL would take the user to the Create Account page, with the referral code pre-filled on the form

Much easier for me to say "Click this" rather than "Go to site, click on Create Account, don't forget to put my referral code in otherwise you won't get the extra 14 days free trial" ...

Thanks. Great product, love it :)