Los Angeles - Nick Cannon has "no muscles" following his recent health problems.

The America's Got Talent host - who was stricken by mild kidney failure over the festive period - is feeling much better, though he is unhappy with his appearance and his condition means he will find it hard to get back in shape.

He tweeted: "Getting back in shape is going to be tuff, the DR said because of my condition my body can't process protein and that's what builds muscle

"Time to work smarter not harder... but I got to get right by the time America's Got Talent starts!

"It's going to be difficult to get my six pack back on this Renal Diet. No muscles, skinny with a gut is not fresh

"Right now In my tanktop I look like Samuel L. Jackson in Black Snake Moan #needtogetbackinshape (sic)"

Back in hospital

Though Nick - who has nine-month-old twins Moroccan and Monroe with wife Mariah Carey - is on the mend, he returned to hospital on Wednesday for a "scheduled procedure".

He tweeted: "Back at the hospital, but no worries its only for the day. I will be back at work tomorrow!

"Not an emergency. This was a scheduled procedure. I just dislike hospitals."

Meanwhile, Mariah is reported to have splashed out $300 000 on a Ferrari for Nick.

The luxury automobile is said to be a get well present for her spouse, Media Take Out have revealed.