Robbie Williams plans to get a tattoo of his children's birthdays - because he can't remember them.

The 'Angels' hitmaker - who has Teddy, six, Charlie, four, and Coco, 11 months, with wife Ayda Field - admitted he ''can't retain'' information such as the fact his son will turn five in October so wants to add to his extensive collection of body art to help him with the facts.

He is quoted by The Sun newspaper as saying: ''I'm going to get a tattoo of the dates my babies were born because I don't know them.

''I don't even know the month Charlie was born, just that he is four years old, no, he's five.

''I don't want any judgements, it's just the way my brain works. I don't retain that kind of information.''

Robbie already has a teddy bear tattoo in honour of his oldest child, and recently claimed he is planning some other body art to pay tribute to his other kids.

For Coco, Robbie will get a Chanel logo in honour of the designer, who shared the same first name with his youngest daughter, while for Charlie, the former Take That star claimed he'll have a rolled up banknote etched on his skin, a reference to cocaine, which is nicknamed Charlie.

Explaining his different tattoos, he said: ''The one that means the most is Teddy...

''Teddy's got teddy. Coco, I think I'm gonna get the Coco Chanel symbol and Charlie I want to get a rolled up bank note - figure it out.''

His children's birthdays isn't the only thing he struggles to remember.

Referring to the letter A being tattooed on his finger, he said: ''I lost my wedding ring twice. Losing things is what I do, hopefully I won't lose this. The A is to signify I'm married to a woman called Ayda.''