Credit: Getty(2)

September is going to be a big month for two of YouTube’s biggest stars, Lilly Singh and Tyler Oakley.

The two creators, who have over 13.5 million subscribers between them, will be featured in YouTube’s soon-to-be-released, amped-up ad campaign. Expect to see their faces popping up on billboards, taxis, buses and subway stops all over New York and L.A., as well in magazines and commercials. Oakley and Singh will join Rosanna Pansinso, Michelle Phan, Bethany Mota, Grace Helbig and more YouTube stars whose fan bases extend far beyond the site.

Singh, known by the username “Superwoman” to her fans, posts witty and inspirational videos that play off of her observational comedy chops. With over 6.4 million subscribers and collaborations with celebrities like James Franco, Seth Rogan and The Rock, Singh is primed for crossover success – though she could have never predicted things would have turned out this well for her.

“I genuinely, when I started my YouTube channel, did not think it would get this big. If you guys had watched me way, way back in the day – I made a tribute video when I hit 1,000 subscribers. It was a Justin Bieber parody that was called ‘Never Say Never.’ That’s the extent I thought I would reach, was 1,000 subscribers. I definitely didn t think it would get this big,” Singh told fans at the Entertainment Weekly and PEOPLE Interview Stage at VidCon 2015.

Related Video: YouTube Star Connor Franta Is Getting into the Music Biz

Oakley, who will be one of hosts of the 2015 Streamy Awards on September 17, has been named by Time Magazine as one of the 30 Most Influential People on the Internet. His first book, Binge – a collection of personal essays dealing with the issues he touches in his videos (pop culture, LGBT community, humor) – comes out in October to the delight of his adoring 7.2 million subscribers.

The new campaign featuring Oakley and Singh begins Tuesday, September 8.

Watch the new videos: