Ewan McGregor and partner Mary Elizabeth Winstead have welcomed their first child together after secret pregnancy

Ewan McGregor has welcomed his fifth child with partner Mary Elizabeth Winstead, after a secret pregnancy.

Clara, Ewan's 25-year-old daughter, confirmed the news in an Instagram post announcing the arrival of her baby brother.

The trainspotting star's daughter shared a couple of photos of her cradling the sweet new born, penning a sweet caption that reads, 'Welcome to the world little brother ❤️ congratulations to my Dad & Mary – this is the greatest gift.'

Mary and Ewan kept the pregnancy under wraps and didn't confirm news of the arrival publicly.

It was up to Ewan's children to share the family's happy news, as Esther, Ewan's 19-year-old daughter, also shared a photo of her new sibling on line, revealing his unique name.

'Met my little brother looking like a pirate. I recommend! Welcome to the family little Laurie,' she wrote.

Ewan was previously married to Eve Mavrakis, a production designer and the couple share four children: Clara, Esther, Jamiyan, and Anouk.

Two of Ewan and Eve's four children are adopted Jamiyan was brought into the family in 2006 after being born in Mongolia, and Anouk was adopted in 2011.

Ewan's fans were quick to send their well wishes to the actor and Mary.

One commenter wrote, "He looks absolutely enamoured with you in the first pic Clara 😢😢😢 this is so cute, congratulations on the new addition to the family!!!"

"Ewan’s first son I believe? Congratulations to you all," another added.

Fellow celebs also took to Clara's post to share their well wishes to the family as Pretty Little Liars star Ashley Benson added a string of red love heart emojis.

Ewan and Mary have  been dating since 2017 having met on the set of TV series Fargo in 2016.

Birds of Pray star Mary split from her husband of seven years, filmmaker Riley Stearns, in May 2017. Later that year, she was seen dating McGregor, who filed for divorce from his ex wife Eve in 2018.