Clara McGregor Introduces Ewan McGregor and Mary Elizabeth Winstead's Baby Boy: 'The Greatest Gift'
In addition to daughter Clara and the newborn, Ewan McGregor is also dad to three other children: Jamyan, 20, Esther, 19, and Anouk, 10
The couple, who costarred in 2020's Birds of Prey, welcomed their first child together, according to the newborn boy's older sisters.
McGregor's eldest child, Clara McGregor, 25, confirmed the birth of her baby brother in an Instagram post on Sunday.
"Welcome to the world little brother ❤️ congratulations to my Dad & Mary - this is the greatest gift," Clara wrote alongside two adorable photos with her sibling.
Clara's younger sister Esther, 19, also welcomed their little brother Laurie into the family on Instagram.
"Met my little brother looking like a pirate. I recommend!," she captioned a trio of sweet images. "Welcome to the family little Laurie."
Before welcoming her newborn, the Kate actress, 36, did not publicly share the news of her pregnancy and was not photographed with her baby bump.
The Halston actor, 50, is also dad to two other children, Jamyan, 20, and Anouk, 10, from his previous marriage to Eve Mavrakis, whom he divorced after 22 years of marriage.
McGregor and Winstead met on the set of the TV series Fargo in late 2016.
In May 2017, Winstead split from her husband, Riley Stearns, after seven years of marriage. That fall, she and McGregor were seen kissing during an outing together.
Months later, the Obi-Wan Kenobi star filed for divorce from Mavrakis in January 2018, citing irreconcilable differences as the reason for their separation. And in November 2019, McGregor asked a judge to declare him and Mavrakis single before finalizing their divorce.
Want to get the biggest stories from PEOPLE every weekday? Subscribe to our new podcast, PEOPLE Every Day, to get the essential celebrity, entertainment and human interest news stories Monday through Friday. And listen below for more on Ewan McGregor and Mary Elizabeth Winstead's baby news.
In January 2020, Winstead spoke to Glamour U.K. about starting over after her first marriage ended. "I got divorced a couple of years ago, which was a scary, crazy thing for me because I had been with the same person since I was 18 years old, and that was what I knew," she said. "I was really starting new as an adult for the first time in my life. For me that was a big turning point, being OK with changing, accepting that change is a good thing and that it's OK not to know where that change is going to take you."
In summer of 2020, McGregor and Mavrakis finally settled their divorce.