The 38-year-old - who made her last appearance in November 2003 - will reprise her Walford role for a single episode, which is due to be filmed in the coming weeks.
Producers are keeping storyline details a closely guarded secret but her character's comeback will see Lisa swoop into Albert Square in a bid to retrieve her daughter Louise (Brittany Papple).
The youngster turned up outside Walford's tube station under mysterious circumstances, having been dropped off by an unidentified driver. Despite Ronnie (Samantha Womack) handing Louise over to Social Services, Louise has since been placed in the care of her father Phil Mitchell (Steve McFadden). Lisa's whereabouts, however, have yet to be revealed.
Over the coming weeks, one local resident will secretly contact Lisa, revealing Louise's location to the concerned mother.
Speaking of her decision to make a whistlestop return, Benjamin said: "I'm really looking forward to returning to EastEnders for this episode. It will be great to see some familiar faces and work alongside old friends again."
Executive producer Bryan Kirkwood added: "Lucy's character Lisa was responsible for one of the biggest cliffhanger episodes in EastEnders, so it's a real treat to have her back on screen."
An insider teased: "Lisa Fowler was a major part of Phil's life - she knows him as well as anyone, so she won't be happy about him looking after his daughter.
"With their history, you know that this storyline is going to be an explosive episode in the Mitchells' history."
They added: "Everyone at EastEnders is keeping really tight-lipped about what might happen and what will be revealed about Lisa's past - but it's bound be another event that will leave Phil reeling."
In 2001, Benjamin was at the centre of the 'Who Shot Phil?' plot, which quickly became one of British soap's biggest whodunnit mysteries.
Following a two-month wait, an estimated 22 million viewers tuned in to see her Walford counterpart unveiled as Phil's attempted murderer. In addition, the UEFA Cup semi-final was pushed back by 15 minutes in order for the schedules to accommodate the extended 40-minute screening.
At the end of last year, Benjamin became the first person to be voted off the ninth series of ITV1's jungle reality show I'm A Celebrity... Get Me Out Of Here!.