Robert De Niro has confirmed his split from Grace Hightower.

The 'Taxi Driver' star has announced he is ''entering a period of transition'' in his relationship with the actress and philanthropist but insists they will remain good friends for the sake of their two children - Elliot, 20, and Helen Grace, six.

He said in a statement: ''Grace and I have two beautiful children together. We are entering a period of transition in our relationship which is a difficult but constructive process. I honour Grace as a wonderful mother and ask for privacy and respect from all as we proceed to develop our roles as partners in parenting.''

Rumours of the pair's split came last week when a source claimed they are not living together and planned to make a formal announcement shortly.

One source told the New York Post's Page Six column: ''They are not living together at this time.''

Whilst an insider added to People magazine: ''Sometimes things don't work out the way you hope or want them to.''

Robert and Grace - who are notoriously private about their relationship - tied the knot in 1997 after 10 years of dating. However, the couple went through a bit of a rocky patch two years into their marriage, which saw Robert file for divorce, but he later pulled the papers. The couple also renewed their wedding vows 14 years ago, joined by their good friends including Meryl Streep, Ben Stiller and Martin Scorsese.