John Krasinski and Emily Blunt are now parents. The low-key Hollywood couple just said hello to their first child together on Sunday.

The proud dad shared his joy on Twitter, instead of announcing it through their respresentatives. He tweeted, "Wanted to let the news out directly. Emily and I are so incredibly happy to welcome our daughter Hazel into the world today! Happy bday!"

Krasinski and Blunt announced that they were expecting a baby back in September 2013 through their representative. They had a baby shower last December in their home in Los Angeles, with a few of their celebrity friends in attendance. Friends actress Jennifer Aniston attended, along with her fiancé and Wanderlust costar, Justin Theroux. Frozen star Kristen Bell and Amy Adams of American Hustle were spotted at the party as well. People reported some details from unnamed source, who said, "Emily seems very excited about the baby and looks great. She opened gifts of baby clothes and plush toys in front of her guests as they enjoyed cookies and chocolate. Everyone was oohing and aahing."

The first-time parents first started dating in 2008. They were steady for two years until they got engaged in August 2009. They tied the knot in July 2010, and had an overseas wedding in Como, Italy.

The Office star and the Devil Wears Prada actress both worked during the entire pregnancy. Blunt has been working on Sister, a psychological thriller based on the novel by Rosamund Lupton. She is also starring in Edge of Tomorrow and the musical, Into the Woods. Krasinski has also been busy during the pregnancy. He has been working with Cameron Crowe's untitled movie that's set for a 2014 holiday run. He also found the time to work on an animated short with fellow actor, Joseph Gordon-Levitt, for Levitt's creative collaborative company, hitRecord. Called Family Patterns: Visuals, it featured an adapted script by Krasinski, but the collaboration has yet to be finished.