Users of the Xbox One and Xbox 360 will be able to sign in simultaneously on a single gamertag, Microsoft has confirmed in a new Ask Me Anything on IGN.
"You'll be able to be signed on with the same gamertag on both an Xbox 360 and an Xbox One console at the same time," wrote chief Xbox One platform architect Marc Whitten. "However, like today, you can only be signed into one Xbox 360 and one Xbox One at a time."
In theory this means you'll be able to have an Xbox 360 plugged directly into an Xbox One, playing GTA 5 on the Xbox 360, then instantly switch to the Xbox One to play Forza 5, all whilst not having to sign out of or into your Xbox Live profile.
Xbox One launches in November priced £429.