Harrison Ford is reportedly planning to adopt lover Calista Flockhart's son.Harrison, who has been dating the 'Ally McBeal' actress since 2002, has formed a close bond with Calista's seven-year-old adopted son Liam and wants to legally become his father.A source said: "Harrison wants to give Liam his name. He adores him as though he were his own flesh and blood. Harrison is the only dad Liam has ever known."However, 43-year-old Calista, who adopted Liam in 2001, is alleged to have told Harrison, 65, he must marry her before the adoption can go ahead.The source added to National Enquirer magazine: "There is just one detail Harrison will have to take care of - marrying Calista. She says it is fine if Harrison adopts her boy, but she wants to walk down the aisle first."The 'Indiana Jones and the Kingdom of the Crystal Skull' actor already has four children.He has two grown-up sons, Benjamin and Willard, with first wife Mary Marquardt.
Harrison also has two children, a son Malcolm and daughter Georgia, from his second marriage to Melissa Mathison. The pair's divorce was finalised in January 2004.