The pair became estranged in 2007 when the actress was accused of stealing Danielle's boyfriend at the time. Wallace dated youth worker Tommy O'Neill for a year before they called off their engagement.
Wallace is said to have contacted Mason to offer the 26-year-old support through the premature birth of her son Rudy. The Sun claims that the pair now hope that their children will be raised as "close cousins".
"Jessie was texting Danielle all through the 72-hour labour," a friend told the paper. "She is determined that this baby is going to heal the rift."
On the birth of her son, Mason said: "Words just cannot describe how much I love him. He is the best thing that could have ever happened to me, the cutest little thing. I just can't wait to get him home from hospital."
She now plans to marry her partner Tony, and hopes Wallace - Kat Moon in the BBC soap - will serve as a bridesmaid.
"I'm so hoping that I can be close to my sister again now," she said. "I'm sure she will love her little nephew."
> Jessie Wallace met fiancé on 'disastrous' blind date