(Reuters) - A collection of late British actress Audrey Hepburn's letters to her mentor go on auction at Bonhams in London on Wednesday.

The series of letters date to the 1950s, a tumultuous time in the late actress' life, and were sent to her acting coach Sir Felix Aylmer. They are expected to sell for up to 4,000 pounds ($5,380).

The letters will be auctioned alongside a collection of guitars owned by the late musician Gary Moore and a notebook belonging to Freddie Mercury, the late star of the band Queen.

(Reporting by Sarah Mills, writing by Gayle Issa)