Britney Spears was allegedly filmed having sex with a stranger she met on vacation, it has been claimed.The 28-year-old unnamed man met the 'Toxic' singer while holidaying in Hawaii last June and secretly recorded them having sex in a bungalow at the Four Seasons hotel on the Kona-Kohala Coast. He claims he has not sold the tape yet because he is embarrassed by his own performance.The man told In Touch Weekly magazine: "It was just normal, we didn't do anything crazy. It was a little disappointing. It lasted for about 25minutes and then we passed out."He claims he met Britney, 25, in a bar at 1am on June 7 2007 and they went back to her room to "party" before "hooking up". Meanwhile, the singer's close friend Sam Lufti has revealed she is "very optimistic" of getting her children back. Britney - who was ordered by a judge to hand over sons, two-year-old Sean Preston and one-year-old Jayden James, to ex-husband Kevin Federline on Monday - now has her legal affairs in order ahead of today's custody hearing. Lufti told People magazine: "Kevin's custody is only temporary."We signed all the necessary documents that she needed to get done and Britney is in a good mood, no problems, very optimistic."Scheduling conflicts and errors in communication led her to believe that her deadline was later this week rather than Monday."The California Department of Motor Vehicles also revealed yesterday that Britney has been issued an interim driving licence. Mike Marando of the DMV said: "She has fulfilled her requirements for a California driver's licence. She took and passed a written test in April. She will be issued a formal licence in the mail soon."Last month, the singer was charged with misdemeanour driving without a valid California licence and hit-and-run after she hit another vehicle in a car park on August 6 and left the scene of the accident. Los Angeles Superior Court Commissioner Scott M. Gordon, who is overseeing her custody case, ordered her to prove she was a legal driver.