The Emmerdale actress, 27, confirmed the happy news on Twitter over the New Year period.
In a message to her 380,000 followers, Charley wrote: "Happy new year everyone. Excited to head into 2016 as a family of 4."
Fans quickly realised that the soap actress and her co-star boyfriend Matthew had already welcomed their second baby!
Happy new year everyone. Excited to head into 2016 as a family of 4— Charley Webb (@MissCharleyWebb) December 31, 2015
Fans inundated the pair with messages of goodwill and congratulations, with one saying: "@MissCharleyWebb Happy New year, to you, @MrMattWolfenden Buster and his new Brother xxx."
Another told confused followers: "Yea Charley had a Baby Boy on the 19th of December."
Baby wolf is too comfy in there pic.twitter.com/2pxCZEVYkv— Charley Webb (@MissCharleyWebb) December 17, 2015
Just a few days before she gave birth, Charley had joked that "baby wolf is too comfy in there"...
Dancing On Ice star Matthew and Charley - whose older brother is Jamie Lomas - is already mum to son Buster, five.
They announced they were expecting their second child last June.
As Charley goes on maternity leave, her character Debbie Dingle was seen packing her bags and fleeing the village in dramatic episodes shown this week.
She finally discovered that her partner Ross Barton had been lying all along and had tried to kill Robert Sudden last October by putting a bullet in his chest.
Bye Debs @emmerdale— Charley Webb (@MissCharleyWebb) January 1, 2016
After visiting her mum Charity Tate in prison and saying an emotional farewell to her dad Cain, we saw Debbie pack the car and leave - with Ross in quick pursuit. Eek!
Meanwhile, Matthew plays David Metcalfe in the ITV soap.
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