Ewan McGregor's daughter Clara has branded her father's lover a ''piece of trash'' in a scathing social media post.

The actor's 22-year-old daughter lashed out at her dad's girlfriend, 'Fargo' co-star Mary Elizabeth Winstead, after a photo of her was shared on an Instagram fan page devoted to the actress describing her as beautiful.

Hitting back with a comment on the picture including laughing and smiling emojis, model Clara wrote: ''Most beautiful and talented woman on earth? Oh man y'all are delusional. The girl is a piece of trash x [sic]''

Her remarks come seven months after Ewan filed for divorce from his wife - Clara's mum - Eve Mavrakis after 22 years of marriage.

Together, the estranged couple also have Jamyan, 16, Esther, 15 and Anouk, six, and Eve previously admitted she was ''disappointed'' by the end of their relationship.

Speaking about his decision to file for divorce, citing irreconcilable differences, Eve said: ''It's disappointing and upsetting but my main concern is our four children are OK.''

The pair announced their split in October last year but court documents filed in January 2018 listed the date of their separation as May 28, 2017.

Eve - who met the Scottish star in 1995 on the set of 'Kavanagh QC' - has maintained a dignified silence on the break-up but did speak out to say: ''It's disappointing and upsetting but my main concern is our four children are OK.''