Kevin Federline is unconcerned over reports his ex-wife Britney Spears has hired a private investigator to unearth secrets about his past. Mark Vincent Kaplan, the star's attorney, insists his client has nothing to worry about if the rumours are true - and warns Spears the investigation is a waste of her money. He says, "I think that if that is what they need to do, or have to do, to have (a go) at it. I don't think it will, in anyway, be a good expenditure of funds. But I can't stop that from happening. "I don't think he (Federline) would be concerned about it, and I don't think he has to change anything he is doing in order to address that." Kaplan, however, praised Spears' decision to hire a chauffeur after she was banned from driving with her two sons, Sean Preston and Jayden James, in the same car. He adds, "Anything that puts the children in a car that reduces the risk... I am all for that. We are only concerned when she is driving the kids." But he refused to confirm or deny reports Spears will celebrate Thanksgiving with her sons. Gossip website TMZ.com reported on Monday (19Nov07) Spears would have access to the kids on Wednesday (21Nov07), with Federline having the boys on Thursday (22Nov07), the official day of the U.S. holiday. Kaplan says, "I think that nobody wants to be celebrating the holidays without their kids. I'm sure that will be worked out in a way that makes sense for everybody."