In a statement posted on her official website, Manning said that she found returning to the role much easier than she ever imagined.
"I was really surprised at how it all came back, and how quickly I felt like Jo again," she said. "It was a genuine pleasure to be playing her once more."
She continued: "And to be inside the Tardis again was the icing on the cake. I love how it's been updated - or retro-dated is more accurate, I suppose."
The actress is to revive the character for a two-part serial called 'Death Of The Doctor', which will also feature an appearance by current Doctor Who star Matt Smith.
Manning acknowledged that Jo has changed dramatically since she left the third Doctor in 1973.
"You'll have to watch the programme to see what I mean, but Russell T Davies has done a wonderful job of showing how Jo has developed over the years.
"You can still see the young and awestruck girl she was, but that's been tempered by experience and maturity - not replaced, but tempered."
The two-parter will see Jo meet fellow Doctor Who companion Sarah Jane Smith for the very first time.
The Sarah Jane Adventures returns for its fourth series in October.