Vanessa Kirby has given birth to her first child

In the post, Rabil - the co-founder and President of Premier Lacrosse League - wrote: "I'm learning that becoming a parent slows you down and wakes you up at the same time.

"I'm really grateful for everyone's health, that I get to wake up every day to mum's enormous love, and that we get to have you in our lives now."

In a nod to his lacrosse exploits, the 39-year-old sports ex ecutive added: "For your first cradle stick. It'll hold many stories and blessings. Likely broken windows too. Balls are allowed in the house."

The couple have not revealed the name or sex of the baby.

Vanessa's pregnancy was revealed earlier this year when she showed off her baby bump during a photocall for her movie The Fantastic Four: First Steps.

The 37-year-old star explained how she got into the motherhood mindset during the making of the superhero film, in which her alter ego Sue Storm/ Invisible Woman also becomes a mother.

Kirby told Entertainment Tonight: "It was a daunting journey because (Storm) really is a working mother, a working superhero mother.

"She was pregnant for half the movie, she gives birth, and I guess something that she really taught me that I didn't fully know is that you can do everything. You can have it all.

"She gave me a lot of confidence in that."

Vanessa filmed scenes for the movie with real babies and "got really attached to them".

The Mission: Impossible actress said: "100 per cent of the film was shot with a real baby.

"Our lead baby, Ada, a little girl, was just heaven. We had lots of other babies who were acting with us and helping us. We got really attached to them, and they were so part of our journey. It almost became weird if they weren't there."

Before finding love with Paul, Vanessa dated the actor Callum Turner for four years but opted to keep the relationship private as the public wasn't interested in the details.

Vanessa said: "I keep my relationship super private.

"He is just completely wonderful and he's my best friend, so that's... I guess you can either choose to talk about it or not. If you talk about it, it becomes interesting to people, but if you don't, then it's not."