The actress's character Cora Cross is in for a shock next week when Ava - her long-lost daughter - turns up on Albert Square after being tracked down by Tanya.
Ava's arrival in Walford comes following Cora's confession that she put her first-born child up for adoption, rather than Ava (Clare Perkins) dying as she had originally claimed.
Discussing the pair's surprise meeting next week, Mitchell told Inside Soap: "It's very important to [Cora] that her daughter knows it wasn't just some one-night stand. Cora loved Ava's father, though she never told him she was pregnant. She loved him but it just ended, like some relationships do."
She continued: "I'd love the writers to bring in Ava's long-lost father. I have suggested it, and in the world of Facebook and social networking, it's entirely possible that people can reconnect.
"What happens with human beings is that sometimes when you are young, you have a great love and later on compromise with the partner you choose - but that first great love never leaves you."
Mitchell also confirmed that there are interesting times ahead for Cora's relationship with Patrick Trueman (Rudolph Walker).
She explained: "There's a story coming up that I can't say too much about, but it involves Patrick needing to be looked after and Cora stepping in. It'll be interesting to see where that goes for the two of them."