Ryan Reynolds and Blake Lively are expecting their second child

Baby bumps don't lie…well, most of the time.

Rumours have been swirling about Blake Lively looking a little rounder than usual around the middle on the set of her upcoming film The Shallows, and it turns out there's a perfectly good reason.

As speculated, Blake, 28, is expecting her second child with husband Ryan Reynolds, 39. Us Weekly and People magazine have both reported the happy news.

"Blake is absolutely thrilled and so is Ryan," a source told People.

Blake and Ryan, who have been married since September of 2012, welcomed their first child, daughter James, in December of 2014.

This is particularly happy news for the couple, following the recent revival of Ryan's movie career with the international blockbuster Deadpool. Meanwhile, Blake's star stock continues to rise, with three films, including The Shallows, due this year.

Hiding a tell-tale bump? Blake on the set of The Shallows earlier this week.

Considering how secretive they were about James – they only released her birthdate on her first birthday! – we probably won't be getting many details about the pregnancy as it comes along.

And we can probably rule out an invitation to the baby shower as well, but congratulations to Blake and Ryan.

Related video: Ryan Reynolds makes cheeky joke about sex with Blake Lively at the 2016 MTV Movie Awards