The appointment of Steve Borthwick as the new England head coach is expected to be announced in the coming days.
Since Eddie Jones was sacked, the 43-year-old has been the overwhelming favorite.
The first match of the Six Nations will be against Scotland.
Borthwick will leave the Tigers after two and a half years.
He played a big part in the win over Clermont Auvergne.
He couldn't say if he'd still be at the helm for the game with Gloucester on 24 December, instead praising his team's ability to win in adversity.
He told the radio that he wanted to enjoy the victory.
The team was built after the Covid Pandemic and has had many challenges.
I'm proud of how hard they train and how much they want to do well for this club.
The Rugby Football Union is expected to confirm Borthwick's departure as early as Monday, according to reports.
Borthwick was supposed to take over from Jones after the Rugby World Cup, but the latter's dismissal has accelerated the process.
Since retiring from playing, the ex-Saracens and Bath lock has built a coaching CV.
After working with Jones as an assistant with Japan and England, Borthwick moved to the bottom of the league table.
The transformation was led by Borthwick and culminated in the title win.
Borthwick leaves the club in good shape. A number of home-grown players have been capped by England during his tenure.
Kevin Sinfield is expected to join the England coaching staff.