Scotland Women will play two test matches against the Springboks in Cape Town. The first will be on Monday (September 30) at 4pm (BST) followed by the second test on Saturday, October 5 at 2pm (BST).
Speaking to the Oban Times before she left Evans said: 'I am really excited to be heading out to South Africa this weekend.
'They are going to be tough matches as South Africa are just one spot above us in the rankings but we are all ready for the challenge and excited by the opportunity.
'The tour itself will also allow for plenty of time for us to spend time together as a team.
'This season we have a new coach in and that has brought with it a new energy. We have had a couple of full squad training sessions with Philip Doyle and I am looking forward to getting to the pitch in South Africa now.
Now living in Newcastle Evans has just started studying sports science at Northumbria University and plays her rugby with Tyrrells Premier League team Darlington at Mowden Park to play club rugby.
This is a big step up and a fantastic experience playing with and against some great players,' she added.
'I'm looking forward to the season ahead.'
Nelson, who plays for Loughborough Lightning, will be taking on the role as tour captain, following a successful season as captain of the Scotland Women 7s squad earlier this year.
The tour will be the first matches under new head coach Philip Doyle's lead. He said: I am really excited to see what this squad can produce in South Africa.
'We have had two very successful training camps with large numbers of players involved.
'Selection has been tough and this is due to the increasing standards of all players. This can only bode well for the rest of the season and shows the depth that we are able to add to the squad.
'I have been really impressed with Helen and she did a fantastic job leading the Scotland Women 7s this season. I am looking forward to seeing how she embraces this opportunity before I finalise my decision on captain for the season.
'I am using this tour to very much look forward to the future.'
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