The model-and-author gave birth to Margot Cullum - her second daughter with her jazz musician husband - on Monday (04.03.13) and the proud dad revealed the couple are ''completely thrilled'' with their new arrival.
Jamie wrote on Twitter: ''On March 4th @sophiedahl gave birth to our second baby girl, Margot Cullum. She is healthy and gorgeous and we are completely thrilled. (sic)''
The 35-year-old writer, who is the granddaughter of legendary children's author Roald Dahl, also has two-year-old daughter, Lyra, with the 'High and Dry' singer and the couple had just celebrated the tot's second birthday on March 2 before welcoming their latest bundle of joy two days later.
Sophie met Jamie, 33, in 2008 and the pair later married in January 2010 in an intimate ceremony for family and friends at a country mansion in England. The couple then welcomed Lyra a year later.
Jamie previously credited his wife for helping him put his life in perspective.
The singer said: ''My relationship with Sophie has helped put everything in perspective. It reminds me that while I love working, and have certain responsibilities to my career, there are more important things in life.''