' winner Stephen Libby had a surprise reunion with host at Liverpool Station on Thursday, as she filmed the new series of The Piano.
As well as hosting the BBC hit show, Claudia fronts 's The Piano.
The show invites gifted amateur pianists to play live at some of the nation's busiest train stations, from London St Pancras to Central to make it through to a grand concert for the finale.
Taking to Instagram, Stephen, 32, shared a selfie with Claudia, 54, and wrote: 'Not who I expected to bump into on my commute today'.
Stephen reportedly quit his day job in cyber security to pursue a career in showbiz following his dramatic victory on the hit series.
He became one of the longest undetected Traitors in the show's history, despite facing several major hiccups along the way.
The Traitors' winner Stephen Libby had a surprise reunion with host Claudia Winkleman at Liverpool Station on Thursday, as she filmed the new series of The Piano
Earlier this month, it was revealed Claudia was back for the fourth series alongside Mika.
Mika will join forces with a number of other faces to judge the musicians.
While at Birmingham New Street Station, Tiffany Poon will join the team, while Jools Holland OBE will be there at London Bridge station, and Jamie Cullum will join the pair at Glasgow Central station.
Composer Hiromi will be there to judge at York station and Alice Sara Ott will be on our screens for the Manchester Piccadilly episode.
And fans will be happy to know that old judge Jon Batiste will return to our screens as well.
Claudia has been part of the show since it premiered.
Meanwhile, her new chat show beat as she pulled in 200,000 more viewers than him for her debut Friday-night programme.
BBC bosses were thrilled with her first episode. One insider said: 'Claudia is a superstar and this is the first time she has done a show like this. It rated really well.
Taking to Instagram, Stephen, 32, shared a selfie with Claudia, 54, and wrote: 'Not who I expected to bump into on my commute today'
Earlier this month, it was revealed Claudia was back for the fourth series of Channel 4 show The Piano
The show invites gifted amateur pianists to play live at some of the nation's busiest train stations
Stephen became one of the longest undetected Traitors in the show's history, despite facing several major hiccups along the way and went on to win the cash pot with Rachel Duffy
'There is no question that she will get better and better – this is her dream and she will stop at nothing to make sure it works.
'Her ratings are better than Graham's, which was perhaps to be expected because it's her first show, but the dream would be that they are both on a level.'
Claudia left her role of hosting Strictly Come Dancing after 11 years to launch her chat show.
