The 44-year-old singer showed off her toned figure in a sparkling leotard while singing the official FIFA song, We Are One (Ole Ole) with rapper Pitbull and singer Claudia Leitte by her side.
The trio danced and jumped around on stage, encouraging the excited crowd of more than 62,000 people to join in during their energetic performance at the Corinthians Arena in São Paulo.
There were initial reports that Jennifer was not going to attend the opening ceremony following her split from Casper Smart – but her heartache seemed far from her mind during her show-stopping stadium act.
Nevertheless, there is already speculation about Jennifer’s love life following the end of her two-year romance with Casper. Shortly before her energetic appearance in San Paulo, Jennifer took to Twitter to deny speculation she has started a new relationship.
People had reported that she was dating Dancing With The Stars professional Maksim Chmerkovskiy – but she denied the claims. "No I’m not #rumours #nottrue," she responded when asked by a fan.
Earlier this week, Jennifer's spokesperson addressed rumours that she was dropping out of the World Cup ceremony.
"Jennifer has always wanted to participate in the World Cup opening ceremonies," a statement confirmed. "We have been trying to work out scheduling and logistics.
"Any statements to the contrary were premature. Jennifer would not want to disappoint her fans or fans of futbol. She will be there."