The position of Expedia's top UK marketer has been vacant since the end of last November, when Beverly Shaw was given a new pan-European role at parent company IAC Travel.
Shaw quit the position after only three weeks, and is to move overseas.
Butler joined Expedia last year from rival lastminute. com, where she was head of marketing.
She will be responsible for managing Expedia's relationship with creative ad agency Clemmow Hornby Inge, which was appointed to the £10m advertising account last year by Shaw.
Shaw also moved Expedia's offline media planning and buying from Media Planning Group to PHD.
Expedia refused to confirm Butler's appointment, but said it was still advertising to fill the post on a permanent basis.