It was confirmed last month that Danniella Westbrook will reappear in Walford with a "big secret".
The Mirror reports that she will make her return at the christening of Heather Trott's (Cheryl Fergison) baby George. In scenes to air this summer, Sam will be seen kissing old friend Minty (Cliff Parisi), leaving Heather devastated.
"Sam certainly creates a stir when she turns up. The question is if she is interested in Minty or is just using him," an insider said.
"Heather is gutted about the kiss because she's liked him for ages. She starts crying and runs away from the church. The christening is in chaos."
The kiss is said to leave the mechanic, who will depart the show later this year, grinning from "ear to ear".
The return of Sam, who is rumoured to be pregnant when she reappears, is thought to tie in with Barbara Windsor's (Peggy Mitchell) exit from the soap.