Anne Hathaway on Keeping Her Pregnancy a Secret While Filming 'The Witches' (Exclusive)

The actress admits to ET that she 'really didn't tell anyone' she was expecting her second child.

If we've learned anything about Anne Hathaway, it's that she can keep a secret! The 37-year-old actress spoke with ET's Nischelle Turner about what it was like playing the Grand High Witch in HBO Max's The Witches while she was expecting her and husband Adam Shulman's second child

Hathaway revealed that while on set of the movie remake, she did not disclose that she was pregnant with her son, Jack. "I didn't really tell anybody that I was pregnant because I was still in my first trimester. Then, when I went into my second trimester during filming, I only told a couple people. But the costume still fit so I didn't feel the need to tell anybody," she shared. 

Hathaway encountered one minor issue when trying to keep her pregnancy a secret from "legend and genius" costume designer Joanna Johnston. 

"She was describing the gloves and the gloves having these little nail inserts ...and the fabric she was going to use and the silhouettes and everything was just great," she recalled. "[Then she said,] 'I think we should get you, like, a little, you know, corset so you have a wasp waist.' And I just went, 'Oh no, I don't like that one. I don't think so.' And she went, 'What, why?' ...And I couldn't say, 'Because I'm five weeks pregnant.'"

Hathaway said she blamed it on the tap dancing the role required. "I go, 'I just know myself as a performer and I'm just gonna feel really constrained. I'm gonna feel really constrained and I just, I'm gonna be funnier if I don't have something,'" she jokingly recollected on what she told Johnston.

The Oscar winner added, "It's such BS but somehow I sold it, and Joanna didn't ask questions. She worked with me and then by the end of the movie, I was 16 weeks pregnant and she got it."

One thing that The Witches did allow for was for Hathaway to reunite with her Devil Wears Prada co-star, Stanley Tucci, who plays Mr. Stringer in the film. 

"I was so happy when I found out that Stanley was going to be in the movie, because Devil Wears Prada was such a special experience," she mused. "...It's become this touchstone movie for so many people, but for us making it, it was such a joy I think in all our careers, a highlight. To get to pick up with Stanley and get to play totally different characters and get to be weird and silly, it was really special. [I] enjoyed it, had a really good giggle."

As for Hathaway's quarantine experience this year, she told ET that she knows it was "probably amongst the least painful."

"I did enjoy being with my family and it was that for me," she said. "There were a lot of silver linings for me in it."

And for those looking for things to watch during this unique Halloween season, The Witches is now streaming on HBO Max.