The happy news was announced at an awards ceremony in Miami, Florida, when fellow signer Carlos Vives said: "Yes, she is pregnant and she's very happy."
Columbian Shakira, 37, already has a one-year-old son called Milan with Piqué, 27, who plays for Barcelona.
They met four years ago when Piqué appeared in the music video for Shakira's hit song Waka Waka (This Time for Africa).
Rumours that Shakira, who is a judge on the US version of The Voice, was expecting again first surfaced after she toned down her trademark belly-dancing during her performance at the World Cup closing ceremony in Brazil two weeks ago.
In January last year, Shakira announced the birth of Milan on her official website , after asking her followers for their prayers before the birth.
She said he was already following in the footsteps of his father, footballer Gerard Pique, stating: "Just like his father, baby Milan became a member of FC Barcelona at birth."
She added in the message: "We are happy to announce the birth of Milan Piqué Mebarak, son of Shakira Mebarak and Gerard Piqué, born January 22nd at 9:36pm, in Barcelona, Spain.
"The name Milan (pronounced MEE-lahn), means dear, loving and gracious in Slavic; in Ancient Roman, eager and laborious; and in Sanskrit, unification..."
Shakira has just celebrated the mind-boggling feat of winning over 100 million Facebook fans.
Who else is pregnant this year?