Mortimer (The Newsroom) has created and will star in Doll & Em, a show about her real-life best friend Dolly Wells.
The series is described as "an intimate, funny portrait of female friendship, set against the backdrop of LA" and will feature a number of celebrity cameos.
Katherine Kelly (Mr Selfridge, Coronation Street) and Anne Reid (Last Tango In Halifax) are among the talent who will star in Reckless, a series of original scripted drama specials.
Sally Wainwright, Gwyneth Hughes and Annie Griffin are among the Reckless writers' team.
Kelly and Reid will star in Wainwright's Last Witch, which is described as an "eerie supernatural tale of revenge".
Sky Living's Antonia Hurford-Jones said: "Today marks an exciting time for Sky Living as we reveal an incredibly strong line-up of talent, who I am thrilled to be welcoming to the channel.
"Each of our new commissions has great storytelling, great characters and engaging relationships at their heart. These are key themes which will run throughout our programming. There's also big terrestrial talent arriving on the channel, both on and off screen."
Other new commissions include a third series of Mount Pleasant and a new sitcom from Thick of It duo Simon Blackwell and Chris Addison.