Britney Spears has a ''flirty relationship'' with David Lucado.

The 'Toxic' hitmaker has been dating the legal investigator for a year and a half, but they still act like a new couple, according to friends.

A source told Us Weekly magazine: ''They have this flirty relationship with a sexual vibe. They laugh a lot, which she needs.

Britney's sons, Sean, eight, and Jayden, seven, have also formed a close bond with David.

The source said: ''Her boys really like him.''