Heavily pregnant R&B singer Kelis is desperate to give birth - because carrying a child is like "living in purgatory."

The Milkshake hit-maker is expecting her first child - a son - with estranged husband Nas this summer and she is more than ready to go into labor.

She writes on her Twitter.com page, "I feel like I have been pregnant forever... OK, yeah, the better part of a year! It's an eternity. My rib cage is being attacked by my stomach which is annihilating my lungs. I want this little Martian now! I can't wait - the suspense is crazy. I hate waiting. I have probably (sic) 6 to 8 weeks left! Longest time in my life! I need to have this baby pronto! I'm over this figure!"

And Kelis is missing her fashion freedom - admitting she is sick of wearing trousers with elasticized waistbands and can't wait to drop the pregnancy pounds and squeeze back into her favorite skinny jeans.

She adds, "Good grief, a girl can only stand but so much Lycra in one lifetime. I have had enough I want corsets and tight jeans and platform stilettos and I want it now!"

The star is due on July 21st. The baby boy will be Kelis' first child and rapper Nas' second. The I Can MC also has a teenage daughter from a previous relationship.

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(This news article provided by World Entertainment News Network)