George Michael may be known for his sweet pop lyrics and charitable generosity, but his ex-manager has revealed that the singer had a will of steel.

George Michael: Manager recalls what the ‘brilliant, cantankerous’ singer was like behind closed doors

The Story of... 'Last Christmas' by Wham!

The Story of... 'Last Christmas' by Wham! - as told by Andrew Ridgeley

Christmas songs

The 50 best Christmas songs of all time, ranked

George Michael released 'December Song' in 2009

Remembering George Michael's beautiful forgotten Christmas track 'December Song' 14 years later

Last Christmas features the music of George Michael and Wham!

Last Christmas movie: The poignant George Michael moment that made us very emotional

Bernie and George Michael on The Catherine Tate Show Christmas Special in 2007

Remembering George Michael and Catherine Tate's incredible cover of 'Fairytale of New York'

George Michael

George Michael documentary maker: No-one would say anything bad about him

Alanis Morissette at Graceland

Alanis Morissette covers 'Last Christmas' at Graceland in honour of Elvis and Lisa Marie Presley

Pet Shop Boys’ Neil Tennant, 69, has recalled a brilliant story about a spat he had with George Michael back in 2012.

George Michael's hilarious spat with Pet Shop Boys' Neil Tennant explained

Frank Sinatra wrote a public letter to George Michael in 1990, criticising him for complaining about fame.

When George Michael received a dressing down letter from Frank Sinatra: 'Stop complaining!'

Wham! George Michael and Andrew Ridgley - Last Christmas

Wham's Andrew Ridgeley talks about hearing the 'Last Christmas' for the first time

Andrew Ridgeley called George Michael "one of the greatest singers of our time".

Wham!'s Andrew Ridgeley emotionally inducts George Michael into the Rock and Roll Hall of Fame

Carrie Underwood once revealed that George Michael had "always been such an influence on me."

Carrie Underwood pays tribute to George Michael with powerful 'One More Try' at Hall of Fame induction

The greatest duets of all time

The 20 best duets of all time, ranked

The greatest songs of the 1980s, ranked

The 100 greatest songs of the 1980s, ranked

Geri Halliwell-Horner has opened up about George Michael's moving gesture of support when she left the Spice Girls at the height of their fame.

Geri Halliwell reveals moving gesture by 'father figure' George Michael after she quit Spice Girls

George Michael's best songs

George Michael's 20 greatest songs ever, ranked