Oscar-winner regularly lied introducing leading parts for Marilyn Monroe (originally Norma) (6)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

Alternate letters of L i E d + initial letters (leading parts) of M arilyn M onroe O riginally N orma. Jack Lemmon won two Oscars, in 1955 and 1973, but not, sadly, for Some Like It Hot