American actress and singer Ashley Michelle Tisdale was treated to a piggy back ride from her High School Musical co-star Zac Efron on Saturday as she celebrated her birthday with a beach party in Malibu, California.Tisdale invited her friends and family to join in the festivities as she turned 26 and she frolicked in the sand with hunky Efron before climbing onto his back for a playful ride as they headed into a friend's house nearby.And the birthday girl was delighted to have her close pal on hand, as well as her boyfriend, music director Scott Speer.She Said "So happy zacary made it to my party!!! He's my brother & best friend!!!"Had such a great birthday party! I'm so lucky to have such amazing friends, family, and man in my life!"