More than 1.2 billion people use Facebook's Messenger every single month - and until now, it's been pretty much the only place Facebook users haven't been hit with ads.
Yeah, that's all changing now.
"People already spend time on Messenger interacting and conducting commerce with businesses and brands they love," Facebook says, "and now with Messenger ads, they have an opportunity to discover experiences directly on their home tab."
Here's what you'll be seeing from today, slowly rolling out across all of Messenger's users as the current Beta program expands.
Messenger ads in the home tab of Messenger. When you tap on an ad, you will be sent to wherever the creator of the ad wants you to go - a website, online store, or seperate Messenger chat.
Click to Messenger ads. When you click on a Facebook, Messenger or Instagram ad, you can be send straight to a Messenger conversation with that business.
Sponsored messages. These will show up in your Facebook and Instagram feeds from businesses you've chatted with in Messenger in the past.
For businesses, you can now add Messenger to your campaigns. You can find out more about that here.