Kelis is pregnant with her second child.

The 'Milkshake' singer surprised fans when she took to the stage at Afropunk Festival in Brooklyn, New York on Sunday (23.08.15) with a large baby bump.

A source told E! News: ''She is really excited about her pregnancy. She has a great support system from her family and friends. She is in really amazing spirits.

''She had a great time at Afropunk this weekend and will continue to perform as long as she feels good.''

Another source added, ''She is several months along and feeling great.''

Kelis, 36, already has one son, Knight - born in 2009 - with her former husband Nas, real name Nasir Jones.

The couple split when Kelis was seven months pregnant and divorced in 2010 after five years of marriage.

It is not clear who the father of her new baby is but last year Kelis was spotted hand-in-hand with a handsome mystery man and mysteriously referred to a new boyfriend simply as ''him''.

When asked about her new relationship, she did not give any details but simply said: ''I feel great actually. I am feeling kind of fantastic.''

It was alleged in December 2014 that she had married the man but it has never been confirmed.