Janet Jackson is suffering from vertigo and a "rare form of migraine".

The singer has been forced to cancel several dates on her 'Rock Witchu' tour after falling ill while rehearsing for her show on September 29, but is now receiving treatment for the previously undisclosed illness.

The illness that forced Janet Jackson to miss concerts in Montreal, Boston and Philadelphia last week still appears to be plaguing the singer, who announced the postponement of three more shows over the weekend.

Janet Jackson kicked off the US leg of her first tour in more than seven years sporting a bizarre futuristic catsuit and wild hair reminiscent of her nineties look.

The 42-year-old - who has been in the business for 30 years - delighted fans at the Los Angeles arena with her raunchy performance last night.

Janet Jackson made a BIG comeback, prompting some critics to suggest that the larger-than-life star needs to either go on a diet or invest in a new wardrobe – and go up a size.

The popstar who is 42 shocked fans with her heavyweight look on her ‘Rock Witchu’ Tour when she showed up on stage wearing a skin-tight yellow body suit that accentuated her curves in all the wrong places.

Janet Jackson's infamous wardrobe malfunction at 2004's Super Bowl has gone down in history -- the phrase has been entered into the English dictionary.

Jackson, who was performing during the Super Bowl's half-time show, was left red-faced after her stage partner Justin Timberlake ripped open her top, revealing a breast.