Yes, it has already been confirmed that BlackBerry was in talks with the dev team at WhatsApp to bring their cross-platform messaging app to BlackBerry 10. WhatsApp at first stated they will not be bringing their app to BlackBerry 10, but with the huge early success of the Z10 all that changed. In an e-mail from the WhatsApp support team it states:
“Hello, thank you for your message. We are working on a native client BlackBerry 10 and soon we will have more news to share. If you have other questions or concerns, please do not hesitate to contact us. We will be happy to help! WhatsApp support team.
There is currently an Android working ported app that is available and can be downloaded here of WhatsApp as soon as the native BlackBerry 10 app becomes available we will update you as well.
Source: BlackBerryItalia