Triumphant J Lo, who began training shortly after giving birth to twins Emme and Max seven months ago, punched the air in delight as she crossed the finish line.
"I'm glad I finished and that I made it out of the water," said the 39-year-old after powering her way through a half-mile swim, an 18-mile bike ride and a four-mile run to raise £70,000 for charity.
"But, more amazing than that, I feel really great that we raised money for the Children's Hospital," added Jennifer, who was cheered on by husband Marc Anthony.
The inspiration for taking on the challenge may have come from a fellow competitor – Jennifer's Wedding Planner co-star Matthew McConaughey. As he crossed the line in one hour and 30 minutes, the buff actor was met by girlfriend Camila Alves and their two-month-old baby boy Levi.
Desperate Housewife Felicity Huffman and her other half, William H Macy, were also among the celebrity contingent taking part.