LONDON, Feb 4 (Reuters) - GlaxoSmithKline has hired Citi, Goldman Sachs and Morgan Stanley as financial advisers on its ViiV Healthcare unit as the drugmaker explores a partial initial public offering (IPO) of its HIV medicines unit, sources familiar with the matter said.

Britain's biggest drugmaker, which is due to release full-years results at 1200 GMT, declined to comment on the news on Wednesday.

GSK first announced in October it was looking to float its fast-growing HIV drugs operation business as part of a plan to reshape its business, in what would be the drug industry's largest ever IPO.

The British group has a stake of nearly 80 percent in ViiV Healthcare, with Pfizer and Shionogi holding the rest.

The appointment of the three banks was first reported by Sky News.

(Reporting by Ben Hirschler; Editing by Martinne Geller)