The Colombian singer, who confirmed her relationship with the Barcelona defender in March 2011, revealed her pregnancy in a post on her official website.
"As some of you may know, Gerard and I are very happy awaiting the arrival of our first baby," she wrote.
"At this time we have decided to give priority to this unique moment in our lives and postpone all the promotional activities planned over the next few days.
"This means I will not be able to be a part of the iHeartRadio Music Festival, but I'm sure this weekend in Las Vegas will be spectacular and I will be closely following everything that happens there!
"I'd like to thank Clear Channel and my fans for their constant love and understanding. Big kiss! And will see you very soon!"
Shakira, who recently featured in the video for her collaboration with Pitbull 'Get It Started', is currently working on her eighth studio album, although no release date has been set.
The 35-year-old was confirmed this week to be joining the fourth season of The Voice along with Usher, as replacements for rested coaches Christina Aguilera and Cee Lo Green.
Watch the video for Shakira's 'Addicted To You' below: