The 31-year-old pop star and the ex-backup dancer, 34, appeared happy and at ease as they watched from the sidelines, accompanied by Federline''s girlfriend, Victoria Prince, and the couple's nearly 19-month-old daughter, Jordan Kay, UsMagazine reported.
Spears and Federline announced their engagement in July 2004, after just three months of dating.
They exchanged vows in September of that year and welcomed their first child, Sean, 12 months later. In September 2006, he was joined by little brother Jayden.
The couple''s relationship was a whirlwind from beginning to end. Just two months after giving birth to their second child, Spears filed for divorce, citing irreconcilable differences.