Michael Douglas has become a grandfather for the first time.

The 73-year-old actor's eldest son Cameron - who he has with ex-wife Diandra - and his partner Viviane Thibes welcomed a baby girl into the world on Monday (18.12.17), the 'It Runs in the Family' actor has revealed.

Cameron shared a picture of Viviane in a yoga pose when she was heavily pregnant and wrote on Instagram: ''Today my appreciation for Mother's all over the world has reached new heights...today I took part in a miracle as my baby girl was introduced to the world through a beautiful Amazon warrior...I'm so proud of you #iloveyou. (sic)''

No details about the baby, including her name, have yet been revealed.

The 39-year-old actor has had a troubled few years but has turned his life around since being released from prison in August 2016 after almost seven years behind bars on drugs charges, and he recently admitted being a father would ''drive'' him even further to do well.

He said: ''I'm really looking forward to it, and I think it's going to be more inspiration and drive to really try to put a nice life together for my daughter,'' he said, adding that though the couple had been thinking of names at the time, they were keeping them to themselves.''

And his famous father - who also has children Dylan, 17, and Carys, 14, with wife Catherine Zeta-Jones - was equally excited at the prospect of becoming a grandparent.

He said: ''I'm going to be a grandfather this month, before the end of the year. I'm very excited. It's about time.''

Cameron also admitted he loves his yoga instructor partner ''more every day''.

After Viviane shared a picture of herself on Instagram reflecting on her pregnancy and regular yoga practice, the 'Loaded' actor commented: ''So proud if you Viviane...I Love you more everyday that I know you.(sic)''