Gemma, 26, had leukaemia when she was a child and Becca, 20, donated bone marrow to her and saved her life.
Their trek through the Thai jungle in November is in aid of Leukaemia Care, as the pair want to do something to help others with the disease.
The gig is at the Vintner's Parrot in Warwick Street, Worthing, featuring local band JAG and starts at 7.30pm. Tickets will cost 3 or 5 on the door.
Last week, the girls accepted a cheque for 100 towards their trip from pupils at West Park School in Goring.
The students raised the money by having a wacky hair and clothes day.
They were also given 100 which was raised at a music quiz held at the Conservative Club in Goring last month and 200 from Durrington High School.
To donate money to the girls or for more information about their trip, visit www.justgiving.com/gemmaandbecca
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