Robbie Williams' mum has pledged to support her son after he was admitted to a US rehabilitation centre yesterday (13FEB07) on his 33rd birthday - branding his decision "the best gift he could have given himself". JAN WILLIAMS praised Robbie's decision to enter rehab for a dependency on prescription drugs, and admits she has been aware of her son's battle with drugs for a long time. She says, "I have known about Robbie's problems for some time and it has been very worrying. "But, from a mother's point of view, going into rehab is the best birthday gift he could have given himself. I shall be sending him loads and loads of love as always. I shall be going across (to the US) at some stage." Williams has previously been in rehab in the mid-1990s after he left boy band Take That, when he was treated for addictions to cocaine, ecstasy and alcohol. He has also been treated for depression in the past.