The actress will reprise her role as Sharon Rickman (previously Watts) on August 13.
Newman explained that she had first started discussing a possible return to Walford for Dean this time last year.
She stated that Dean's return, along with the comebacks of Bianca (Patsy Palmer) and Carol (Lindsey Coulson), will provide great storylines for EastEnders over the next 12 months.
"It took a year of negotiations and talks to get Letitia back on the show," Newman told the Daily Star.
"In the end we convinced her and it's great having her back. She's got some big things coming up and we're all very excited.
"Obviously we've got the return of Bianca and Carol and their brood to look forward to this autumn and with Sharon now in the mix we're very happy."
She added: "There are no plans to bring anyone else back at the moment."
Letitia Dean has stated that she originally felt "nervous" about returning to the BBC soap.
Watch a trailer for Sharon's return below: