Social TV app zeebox is adding as many as 15,000 new users every hour following the launch of a new TV ad campaign over the weekend.

The 30 second ad slots, which portray zeebox as TV’s new sidekick, debuted during Sky’s Premiership coverage before being rolled out across its primetime channels.

Zeebox co-founder and CEO Ernesto Schmitt tweeted the figures this morning:

The ad campaign comes after BSkyB acquired a 10% stake in the social TV startup – the deal entitled BSkyB to exclusive UK rights to integrate Zeebox into its own mobile apps.

The broadcaster’s ad team, Sky Media, also secured the rights to sell sponsorship and product placement opportunities around zeebox’s ‘Zeetags’, which give additional information on characters and topics being shown on-screen.

TV ads are the perfect way to promote zeebox as it captures the app’s target user base, and it also suggests that the app’s backers are confident they are onto a winner if they are willing to splash out on high profile TV ad slots.

With all the focus on connected TV recently, zeebox’s growth shows that the real opportunity may be with second screens.

Zeebox allows users to interact with friends and buy products they see on-screen through its smartphone and tablet apps – something that would be more difficult to do through a TV set while the programme is still on.

Last week MTV launched a similar app called ‘Under The Thumb’ which allows users to watch on-demand content simultaneously with friends and chat about it in the app at the same time.

However in an interview with Econsultancy last month, blinkx CEO Suranga Chandratillake said that though second screens had a role to play in the way consumers engaged with connected TV, in the long term the “TV will remain lord of the living room.”