Williams, 36, was recently at a press conference in London to announce the dates of his new tour with Take That.
He was later asked by British newspaper The Guardian if he would be rejoining Take That if he was still having chart success as a solo singer.
Williams replied: 'Greatest Hits album No 1 in 14 countries; last album sold more than The Circus [Take That's last record].'
He then added a joke 'f*** off' to the journalist as his bandmate Mark Owen added: 'It's a sore point.'
Williams was also asked what he would say to Take That fans who believe the band was doing well without him.
He said: 'See you at the Stadium of Light, Monday 30 May 2011.'