Emily Blunt Jokes Daughter Hazel Is Losing Her British Accent: 'I Was Really Proud' of Her Pronunciation

Emily Blunt might have to say “Cheerio” to her daughter Hazel‘s British accent.

The mother of two — who shares Hazel, 2, and Violet, 4 months, with husband John Krasinski — spoke to Jimmy Fallon about her older daughter’s changing pronunciation.

“Hazel had my accent for a really long time and would say things like ‘water’ which I was really proud of,” Blunt, 33, told Fallon on Monday night’s episode of The Tonight Show Starring Jimmy Fallon.

“And then the other day she goes, [feigning American accent] ‘Can I have some water?’ And I went, ‘It’s water.’ And she was like, ‘No, it’s [American accent] water.‘ ”

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And as she picks up her dad’s accent, Blunt says her toddler was also picking up her baby sister Violet. As for how bringing home baby has been for her tot, Blunt says Hazel is taking to her new role as big sis surprisingly well.

“We were concerned Hazel would be disinterested and … she quite likes her,” Blunt says. “I turned my back for a second yesterday and I went to the kitchen to make us some lunch and I came back to discover Hazel just dragging Violet off her play mat … Violet looked a bit wide-eyed and I just said, ‘Oh, Hazel, I don’t think we want to do that.’ And she goes, ‘I just want to get her in a better spot.’ ”

Blunt also talks to Fallon about how she tried to keep her pregnancy with Violet under wraps while shooting her latest film, Girl on the Train.

“I had very hideous costumes … horrible overcoats,” she says, when asked how she kept her bump covered. “There are a couple of stunts in it, so I was being a bit wussy about standing up too quickly, and Justin Theroux — who is fabulous and in the movie with me — he’s been a friend of mine for a long time and he was like, ‘Are you pregnant?’ and I was like, ‘Yes, but you can’t tell anyone.’ He was the only one.”

Last week, Theroux talked about the moment he realized his friend was expecting baby No. 2.

“She was not giving a word up, and I was like, ‘Why are you behaving so weird in rehearsal?’ ” Theroux, 45, told PEOPLE Now. “She was not wanting to jump or run … and this was the woman who did Edge of Tomorrow, this was the woman who has done Sicario, so I know she can handle herself.”

And the not-so-subtle hints kept coming when Theroux and Blunt took a break from rehearsal.

“We went back to my place and I was like, ‘Do you want a drink? Do you want a beer or something?’ ” he said. “And she was like, ‘No, I’m just having a green juice and coconut water.’ I was like ‘What’s going on here?’ ”

— Blake Bakkila