Nicola turns the screw on Sharon in Thursday's EastEnders on RTÉ One and the RTÉ Player.
Teasing what's ahead with first-look pictures, the BBC soap said: "Nicola decides to play her trump card against Sharon over her night of passion with Grant.
"Will her threats be enough to stop Sharon telling Teddy that Barney is Zack's biological son?"
Fans can watch what happens next on Thursday on RTÉ One and BBC One at 7:30pm.
EastEnders airs on RTÉ One and BBC One Monday to Thursday.
