This video was part of a larger post that included the most awesome proposal, complete with Tennant's help, but Cates Holdness had an excellent point about something that Richard James casually mentioned at the end.
Let's put this fantasticness front and center, shall we?
When a fan asked him which companion The Doctor's preferred more between Donna and Rose, Tennant answered and pretty much sent most shippers insane.
Yep.