ADVPN 2.0 Inter region traffic flow

Hi,

  Have a query around ADVPN inter region traffic flow. 

Lets consider we have two regions and each region has their own Hub to advertise the regional LAN summary routes to its regional spokes. And both the hubs have eBGP neighborship between them to exchange regional summary routes

In this scenario, can understand region 1 spoke can form an advpn tunnel with region2 spokes but there are no mention about whether ADVPN will work between region 1 spoke to region 2 hub?.. There is no clear documentation about this in 7.4/7.6 documentation. 

Regards

Raja