Just under ten minutes remain until kick-off at Cape Town Stadium!
South Africa 'A': 15 Willie le Roux, 14 Cheslin Kolbe, 13 Lukhanyo Am (captain), 12 Damian de Allende, 11 Sbu Nkosi, 10 Morné Steyn, 9 Faf de Klerk, 8 Jasper Wiese, 7 Pieter-Steph du Toit, 6 Marco van Staden, 5 Franco Mostert, 4 Eben Etzebeth, 3 Trevor Nyakane, 2 Joseph Dweba, 1 Steven Kitshoff
Replacements: 16 Malcolm Marx, 17 Coenie Oosthuizen, 18 Vincent Koch, 19 Nicolaas Janse van Rensburg, 20 Rynhardt Elstadt, 21 Herschel Jantjies, 22 Jesse Kriel, 23 Damian Willemse, 24 Kwagga Smith, 25 Elton Jantjies
British and Irish Lions: 15 Anthony Watson, 14 Louis Rees-Zammit, 13 Chris Harris, 12 Bundee Aki, 11 Josh Adams, 10 Dan Biggar, 9 Conor Murray (captain), 8 Taulupe Faletau, 7 Tom Curry, 6 Josh Navidi, 5 Iain Henderson, 4 Maro Itoje, 3 Kyle Sinckler, 2 Ken Owens, 1 Wyn Jones.
Replacements: 16 Luke Cowan-Dickie, 17 Mako Vunipola, 18 Zander Fagerson, 19 Adam Beard, 20 Tadhg Beirne, 21 Sam Simmonds, 22 Gareth Davies, 23 Elliot Daly.
Nienaber, meanwhile, is hoping for an improved performance from the Boks after a 40-9 victory over Georgia at the start of the month.
He told reporters: "It is important for us to improve on our performance against Georgia in this match.
"There are boxes we want to tick, for example starting the match better, and delivering an 80-minute performance.
"This is a physical British & Irish Lions team and we know if we give them a sniff, they will punish us, so it is vital that we pitch up from the first minute."
Gatland has welcomed the Springboks naming a strong squad for Wednesday's clash, saying: "I'm really pleased with how strong that team is."
For the British and Irish Lions, Owen Farrell will lead the side.
Springbok head coach Jacques Nienaber has named a star-studded squad for the encounter which includes 18 World Cup winners, with Lukhanyo Am handed the captain's armband in the absence of regular skipper Siya Kolisi.
Hello and welcome to our coverage of the eagerly anticipated clash between the British and Irish Lions and South Africa A at Cape Town Stadium.
We're finally under way at Cape Town Stadium! Referee Jaco Peyper blows his whistle as the Lions kick-off...
The Springboks make a flying start to the game but the Lions earn a penalty and Farrell sets up an attacking lin-up on South Africa's 22m line with a superb touch finder.
South Africa A quickly regain possession of the ball, though, after a turnover penalty. Faf de Klerk turns the tables as he hits a good touch finder, setting up the hosts on the visitors' 5m line.
The Boks almost grab and early try through Sbu Nkosi as he powers over the line but his foot was out of play and Peyper awards a penalty for an infringement in the build-up.
Morne Steyn converts the spot-kick as South Africa break the deadlock early on.
The Springboks are looking very strong early on but it is the Lions who win the first scrum of the evening. Lions are awarded a penalty and they kick for the corner.
The hosts hold firm, though, as the Lions concede a penalty for failing to release on the floor.
TRY!!! South Africa 'A' hit back almost immediately, adding a try to their earlier penalty as Sbu Nkosi goes over on the left corner after Eben Etzebeth charged down Owen Farrell's attempted kick.
Morne Steyn makes no mistake, adding the extras to give the hosts a 10-0 lead.
The Lions look a bit rattled as, after attempting to find touch, Farrell fails to hit the target, allowing south Africa off the hook. Penalty to the hosts, who opt for a scrum on the halfway line.
A series of delays now as Peyper is not happy with the scrum. SA 'A' eventually earn a line-out on the Lions' 22m line.
Penalty to South Africa 'A' following a rolling maul and they kick for the corner, chasing a second try.
The Boks win another penalty and opt for a scrum 5 meters out for the B&I lions try-line.
However, the Boks are penalised for collapsing the scrum, much to the joy of the Lions players.
The Lions are on the board as Farrell converts a spot-kick after Etzebeth was penalised for not rolling away.
Morne Steyn hits a good touch finder as SA 'A' setup for a line-out on the halfway line.
TRY!!! The Springboks are firmly in control now as skipper Lukhanyo Am latches onto an offload pass from Cheslin Kolbe before racing over the line unopposed. Steyn adds the extras and it's now 17-3 to the hosts!
The Lions looking to hit back quickly as they kick for the corner after winning a penalty.
The Lions win three penalties in quick succession but they are unable to find a way through a staunch Springbok defence.
Halt-time at Cape Town Stadium as South Africa 'A' go into the break with a 17-3 lead! However, it has come at a big cost, with the hosts down to 13 men after two yellow cards in quick succession.
The Lions look to strike quickly and seemingly pulling one back through Wyn Jones before the try is ruled out following a TMO review.
Oh dear! Another blow for the hosts as Marco van Staden joins de Klerk in the sin-bin. South Africa down to 13 men! Peyper had enough the repeated infringements from the hosts and the Lions will certainly be confident of a turnaround in their fortunes thanks to their numerical advantage.
A blow for the Boks as De Klerk is yellow-carded for not using his arms in the tackle. He's off to the sin-bin...
Morne Steyn gets us under way in the second half with a deep kick. South Africa 'A' can expect a stern test of their defensive capabilities with two players currently in the sin-bin.
Early change from the hosts as Trevor Nyakane makes way for Vincent Koch.
Another change for the Boks, Rynhardt Elstadt coming on in place of Pieter-Steph du Toit.
So far, so good for the hosts as the Lions are yet to make any significant progress in the final third of the pitch.
With South Africa down to 13 men it was only a matter of time... The Lions get the breakthrough they are looking for as Wyn Jones bundles the ball over the line from close range, Farrell kicking the extras to make it 17-10.
Change for the Lions now as Mako Vunipola is on for Wyn Jones, who looked to have suffered a shoulder injury in the process of scoring the try.
Finally! De Klerk is back in the action with Van Staden set to join him on the field shortly.
Penalty to the Lions and Owen Farrelll points to the poles before slotting the spot-kick from 35 meters out. The Springboks lead by just four points.
It's end to end stuff here with South Africa 'A' back to 15 men on the pitch. The Lions have a 22m line-out, looking to push on and grab the lead for the first time.
The wall of green holds firm, frustrating the Lions who can't breach the defence on the 10 meter line.
Try review after Louis Rees-Zammit touches down on the left, stretching to get the ball over the line. However, the try does not stand and the Springboks' slender lead remains intact!
South Africa 'A' with an almighty push at the rolling maul, winning back some ground. The hosts eventually win a penalty after an infrigement by Mario Itoje but Steyn's kick drift narrowly wide of the left post.
Double change for the visitors as Adam Beard and Zander Fagerson replace Kyle Sinckler and Iain Henderson.
Bok substitute Malcolm Marx steals the ball at the breakdown and the ball is eventually kicked for touch on the Lions' 22m line.
The visitors have seen plenty of the ball (69%) but have struggled to make it count. Time is quickly running out for the Lions to do something here as the Boks look to launch an attack of their own with a kick for the corner.
The Lions win the ball back at the line-out, though, as they prepare for a scrum on their own try-line. The visitors manage to escape unscathed with a good box kick.
The Boks with possession of the ball now. Time is quickly running out for Gatland's men to rescue something from this game.
Steyn tries his luck with an attempted drop goal but his kick again drifts wide of the mark.
Five minutes remaining - can South Africa 'A' hold on for a famous win?
Steyn finds touch on the B&I Lions 22m line as the Springboks make one last push to the put the game to bed.
No luck for the B&I Lions as Fagerson knocks the ball on in a dangerous position.
The Lions force a turnover and earn a penalty in their own half. They find touch on the hosts' 22m line - will there be a late try?