The 38-year-old, who is already to 14-month-old Olive, subtly revealed the news during an acceptance speech for a beauty award in New York.
"I am so proud to accept this in celebration of women, including my daughter and my future daughter," Drew said at the 2013 Beauty Inc Awards, where she won 'newcomer of the year' for her brand FLOWER Beauty.
The 50 First Dates star showed off her blossoming baby bump last month with a dazzling red carpet appearance at the Baby2Baby Gala which was held in her honour.
Wearing a floaty dove grey and white patterned floor-length gown, the Hollywood starlet was utterly radiant ahead of the birth of her second baby girl.
Drew and her husband Will Kopelman announced their happy news at the beginning of November.
"Last time I never commented on it and people just stalked me the entire time," Drew told PEOPLE. "So yes, it's happening, it's true. I tried to keep it a secret for as long as possible."
"Will is just thrilled — we both are," said Drew. "We just wanted so badly for Olive to have a sibling. In some ways, it's really for her. So congratulations, Olive!"
The doting mother gave birth to her daughter Olive in September 2012. "She's a sweet person, which is all I care about," said Drew. "I am obsessed with nice. That's the most important thing."
The Never Been Kissed actress recalled the joyous moment when she found out she was pregnant again.
"I was overjoyed," said Drew. "It always feels so surreal, it's incredible. [I'm feeling] incredible, that, 'Here we go again' feeling. And blessed. Blessed."