Robbie Williams looks slimmer than ever in behind the scenes video after four stone weight loss

ROBBIE Williams sparks concern with his fans after looking thinner than ever following his rapid four-stone weight loss.

The Angels singer wore a serious expression as he did a slow twirl in a glittery blazer and a pair of loose-fitting black trousers as he prepared to go on stage.

The singer has embraced his silver hair and is currently rocking a mullet.

The video was shared on Robbie's wife Ayda Field's Instagram, and she added the caption: "How Robbie gets ready for a gig".

Fans showed their concern for Robbie, with one writing: "Looks far to skinny, there's being healthy then going to far." (SIC)

"You look tiny, Robbie," another said.

"If his wife can't see this," a third added, with a shocked emoji.

Although some people found it inappropriate to comment on his appearance.

One wrote: "Same people that say he is too skinny will be the same people who would have complained he was too fat. Why are people so comfortable with commenting on someone else's weight on that someone else's pictures."

A second agreed: "Shut up everyone! Yes maybe he looks too skinny for us, but have you considered his back pain problems, at his age, he could do so much tour maybe?"

In April this year, Robbie said how he shed four stone after ditching his 40-a-day cigarette habit and hit the gym.

Speaking of his new wellness venture, he told The Sun at the time: "Sometimes now, though, Ayda will turn to me on the sofa and say, ‘We should do sex,’ and I’m sitting there eating a tangerine and just sort of shrug."

Robbie has also become an artist in his own right, sharing illustrations that he does on his computer.

Many of them have powerful or thought-provoking messages.

A recent one was of two stick figures having a conversation with the words: "My ideal goal weight is people being worried about me."

One of the people says: "It's gone too far," while the other smiles back and says: "Aw, bless you."

In the caption he wrote: "So , If a genie appeared and said you can either have your super power be the ability to fly or eat what you want and remain at your goal weight ?

"I would go for Goal weight eating everyday . What about you ?

"I could write a book about self loathing where my body image is concerned . Like pure self hatred , The ugliness of feeling ugly .

"Im body dysmorphic and on top of being dysmorphic at times I can be 40+ pounds over weight .

"So you can imagine what my mind see's .Or maybe you can’t either way its a f****** disaster .

"At the moment i'm skinny ..But me being me my mind is going ‘F****** great Rob , you managed to get skinny and now your old, congrats, golf clap'." (SIC)

He said how "the struggle is real" and that it's something he's battled his whole life.

The singer also said that he wasn't "fishing for compliments" and that he wanted to share in the hope that someone might feel less alone.