Henry Cecil's Apple Charlotte is limbering up to take on some smart US fillies in Sunday's American Oaks at Hollywood Park.After winning her first three starts, the daughter of Royal Applause lost little in a short-head defeat by Splashdown in the Lord Weinstock Memorial Stakes at Newbury when conceding 3lb.Joining the field are Irish 1000 Guineas fourth Rare Ransom, trained by frequent American visitor Dermot Weld, and New Zealand contender Puttanesca.Many potential opponents are from the California area, while Sands Point Stakes winner Gozzip Girl is set to make the trip from New York.Apple Charlotte is owned by De La Warr Racing, whose manager Ed Sackville said: "She's out there now and the plan is for Mike Smith to ride her. It's pretty much an all-American affair, apart from Dermot Weld's filly."This will be easily her toughest challenge, but she had the invitation, so why not run?"Considering her penalty, she ran a very good race in defeat last time to an improving rival."Post-American Oaks targets are yet to be decided and Sackville continued: "At the moment the plan is to bring her back here after the race, but we are very much taking it one step at a time."