The 'Candy' singer has teamed up with his former songwriting partner for the trio of shows at the venue, which kick off tonight (November 22).
In a new video of backstage rehearsals, Chambers is seen accompanying Williams on piano for at least one song.
Williams said: "My erstwhile songwriting partner is here.
"He's my brother, and it's great sharing a stage with him and I love him to bits."
Chambers added: "The last time I was playing on a stage with him was 10 years ago, so it will be very nice to do it again.
"It's going to be very emotional because my children are coming, and they've never seen me in an arena. They've seen me in a local pub, but they haven't seen me doing a massive gig with a massive superstar."
Robbie Williams and Guy Chambers co-wrote most of the singer's tracks up until his 2002 album Escapology.
However, the pair suffered a falling out in the mid-2000s, before befriending each other again several years later. They co-wrote the track 'Blasphemy' on Williams's 2009 album Reality Killed the Video Star.
They will also team up for the upcoming Hillsborough charity single cover of 'He Ain't Heavy, He's My Brother' by The Hollies. Chambers is producing the track, while Williams will provide vocals.
Robbie Williams will headline three nights at the O2 Arena on November 22, 23 and 24 in support of his new album Take the Crown.
Watch Robbie Williams perform 'Blasphemy' live below: