Second row Lewies, who won a single cap for the Springboks in 2014, joined Harlequins ahead of the 2019/20 campaign and has been chosen to replace Chris Robshaw, who is moving to the USA, as club captain in his second season.
“It’s a massive opportunity – a huge honour,” said Lewies. “It comes with big responsibility but it’s something special and I’m really excited.
“Never in my wildest dreams when I signed did I think I’d be in this position.
“Gussy [Harlequins head of rugby Paul Gustard] gave me a phone call and said he wanted to make me captain. I asked for a few days to reflect on it.
“It’s a big decision and it has to be best for the team so I made a few phone calls to some of the senior players – Danny Care, Joe Marler, Mike Brown – to get their thoughts.
“You need those senior players buying into a leader. They’ve been part of this club for a long time. It’s not a one-man job; it’s a team effort.
“They were massively supportive, all three of them, so after speaking to them I had more confidence in the role and I accepted it.”
Gustard said Lewies, 28, has “universal respect across the club”. He follows in the footsteps of another South African, Andre Vos, in becoming captain at Quins.
He has been joined by Boks Wilco Louw and Andre Esterhuizen at The Stoop, giving the club a distinctly South African feel.