The event followed the birth of Mulligan's second child with husband Marcus Mumford, according to Us Weekly. People had asked the actress about being a mom-of-two at a press conference for "Mudbound" on Monday.
"It's good, thank you!" she responded.
Mulligan and Mumford, the lead singer of the band Mumford & Sons, married in 2012, and welcomed their first child, daughter Evelyn Grace, in September 2015.
The actress told Vogue prior to Evelyn's birth that she and Mumford try their best to balance their busy schedules.
"Like anyone, you try and split your time evenly," she told the magazine. "Marcus is the only thing that's mine that I can keep totally away, so I try to."
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