The 24-year-old singer - who is dating Gigi's brother Anwar, 20 - spoke out about Gigi's pregnancy during an interview on New Zealand radio station The Edge and confirmed she knew about the news before it was revealed this week.
Dua was asked: ''Technically, you're going to be an auntie?'' and replied: ''Yeah. It's very exciting news. We're very, very excited.''
The radio presenter then went on to say: ''It's going to be one hell of a baby shower you, Zayn, the Weeknd (Gigi's sister Bella Hadid's boyfriend). How long have you been sitting on this secret?''
However, Dua would not confirm how long she has been aware of the news and would only say: ''Ah you guys are really putting me in a... not long! not long!'
When pressed further, she added that she knew about the pregnancy ''a little bit'' before it was revealed this week.
Meanwhile, Gigi, 25, has confirmed her pregnancy and revealed she's ''very excited'' to become a mother.
Speaking in an interview on 'The Tonight Show starring Jimmy Fallon', she said: ''Obviously, we wished we could have announced it on our own terms but we're very excited and happy and grateful for everyone's well wishes and support. Especially during this time, it's a nice silver lining to be able to be home and be together and really experience it day by day.''
During the interview, Gigi also spoke about her recent 25th birthday celebrations, which saw her receive a special cake in the shape of an everything bagel, which was made by 'Cake Boss' star Buddy Valastro.
And the model admitted she was moved to tears by the impressive patisserie treat, though she isn't sure if the emotions were caused by her pregnancy hormones.
She added: ''I don't know if it was my hormones right now or just like quarantine emotional-ness, I cried every five minutes for an hour every time I thought about how Buddy made my cake.''
Gigi and Zayn, 27, first started dating in 2015 and have had an on /off relationship since then. They got back together last year after a year-long split and their baby is reportedly due in September.
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