Which Total Jackass Told Lisa Kudrow She Was "F*ckable" on the Set of Friends?

Lisa Kudrow dropped by Watch What Happens Live on Wednesday and naturally, the conversation turned to her hit show Friends. When asked by a caller if she could recall the worst behavior by a guest star on the series, she had a pretty disturbing answer: "I rehearsed without makeup most of the week and then on show night I'm in hair and makeup and I was told, 'Oh wow, now you're' — can I say it? 'Now you're f*ckable," Lisa explained, adding, "That's bad behavior, I say." Fellow guest Jennifer Beals asked if Lisa retaliated, to which she responded, "I told Matt LeBlanc. He's like a big brother."

During the aftershow, Andy tried to get Lisa to name names, but all she would reveal is that the rude star was not Charlie Sheen. Phew. Friends was on for 10 years and welcomed nearly 50 male guest stars, so the list of culprits is pretty extensive — but that won't stop us from trying to figure out who this jackass is. Thoughts?