A strong family bond. Michelle Williams' 17-year-old daughter Matilda has found a "wonderful father figure" in stepfather Thomas Kail, a source exclusively reveals in the new issue of Us Weekly. "Matilda is a very mature and intelligent young lady," the insider shares, noting it has been "hard" for Williams, 42, to watch her eldest child get older. "But they wouldn’t change a single thing about their life together." Hahn Lionel/ABACA/Shutterstock According to the source, the actress and her husband, 44, are "soaking up the joy" after welcoming their second child together. (The birth of William's third child was confirmed earlier this month after the family was spotted on a walk together.) “It’s just a dream come true for the whole family," the insider adds. Williams first became a mother after giving birth to Matilda in 2005. The Dawson's Creek alum shared her daughter with late actor Heath Ledger, whom she dated from 2004 to 2007. The Dark Knight star passed away at age 28 in 2008 from an accidental overdose. The Manchester by the Sea actress later moved on with Phil Elverum. The former couple secretly tied the knot in 2018, but they called it quits less than one year later. After working together on Fosse/Verdon, Williams and Kail started dating. Us confirmed in December 2019 that the pair were engaged and expecting their first child together. They exchanged vows in March 2020, three months before their son was born. (The director, for his part, was previously married to actress Angela Christian from 2006 to 2019.) Earlier this year, the Blue Valentine actress revealed she was expecting her second child with Kail. “It’s totally joyous,” Williams told Variety in May. “As the years go on, you sort of wonder what they might hold for you or not hold for you. It’s exciting to discover that something you want again and again, is available one more time. That good fortune is not lost on me or my family.” Since then, the Montana native has expanded her family again with the arrival of her third child. The source reveals that Williams was able to stay tight-lipped about the news due to a "very tight circle of loved ones" that she trusts "implicitly." "She prides herself on living a low-key lifestyle in a super private part of the world, so it’s not like passers-by are going to take her photo or gossip about her being pregnant," the insider tells Us. "That said she was very low-key during the pregnancy and didn’t do much if any traveling, she was a real homebody and Thomas was looking after her and running most of the errands so she could get as much relaxation as possible.” For more insight on Williams and Kail's home life as a family of five, watch the video above and pick up the new issue of Us Weekly, on stands now.