Ms Denham added she was pleased WhatsApp had signed the agreement to cease sharing until it can do so in compliance with the forthcoming General Data Protection Regulation (GDPR), due to come into force in May.
Previously, UK's Information Commissioner's Office (ICO) an concluded an investigation into both WhatsApp and Facebook to see whether or not WhatsApp could legally share users' data with its parent company under UK laws.
Denham said her investigation found that WhatsApp "had not identified a lawful basis of processing for any such sharing of personal data" and failed to provide "adequate fair processing information to users" regarding any sharing of their personal information.
Back when Facebook paid a ludicrous amount of money for WhatsApp back in 2014 people started worrying about whether the messaging app's privacy stance would die off. Facebook promised that it wouldn't, but then changed its mind two years later.
GDPR will replace the current patchwork of national data protection laws, give data regulators greater powers to fine, make it easier for companies with a "one-stop-shop" for operating across the whole of the EU, and create a new pan-European data regulator called the European Data Protection Board. It will also bolster the requirement for explicit and informed consent before data is processed, and ensure that it can be withdrawn at any time.More news: South Jersey teen moves on to next round on ABC's 'American Idol'
As WhatsApp has agreed not to share data with Facebook, for now at least, the firm has not incurred a financial penalty.
I found that if they had shared the data, they would have been in contravention of the first and second data protection principles of the Data Protection Act.
Denham also found that WhatsApp can not and, thanks to the newly signed agreement, will not share user data with Facebook for anything other than basic data processing.
That same month WhatsApp also suspended such data sharing activity in the UK.
Denham said she had reached the conclusion that an undertaking was the most effective regulatory tool to use in this case, and in light of WhatsApp's assurances that no United Kingdom user data has ever been shared with Facebook other than as a "data processor", the ICO has not issued a monetary penalty under the Data Protection Act against WhatsApp. I would also like to stress that signing an undertaking is not the end of story and I will closely monitor WhatsApp's adherence to it.