Writing on her website, Shakira told her fans: "As some of you may know, Gerard and I are very happy awaiting the arrival of our first baby! 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."
Shakira - who has just signed up to become one of the coaches on the US version of 'The Voice' - has been dating Gerard for around two years although she only confirmed their relationship last year by posting a picture of the pair on twitter and Facebook with a caption reading, "I present to you my sunshine." in Spanish.