The pair's intimate moment occurs after Billy jumps to Jean's defence at the club, having seen a group of lads making rude gestures at her.
Billy has been helping out in the club as a one-off, but when his overreaction causes a commotion, he's sent home by a disappointed Jack.
However, rather than returning back to his house, Billy heads over to Jean's for a cup of tea - and it's not long before their unexpected kiss takes place…
EastEnders airs tonight at 8pm on BBC One.
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