She joins the hotel giant as director of external comms, leading global corporate strategy across the various brands and regions. Her remit includes financial PR and crisis management.
‘I was looking for a new opportunity and this role, with a global remit, presented a new challenge,' Williams said.
Williams spent four years at lastminute.com. She joined as a PR manager and was promoted to head of corporate comms (Europe) in 2004.
Lastminute.com did not comment on Williams' replacement, who is understood to have already been appointed. In the new role, Williams reports to vice-president of global affairs Leslie McGibbon.
She replaces Fiona O'Farrell, who is currently director of corporate, crisis and issues at Publicis Consultants.