The 23-year-old all-rounder has been selected after his outstanding performances for Western Province in the domestic One-Day Cup, helping his side win the title with a match-winning effort in the final against North West.
Mpongwana scooped up the player-of-match award after scoring 105 in a total of 307-8 before taking 3-32 with ball to help the home side to a comprehensive 107-run victory.
It is not only the runs and wickets column that has caught the eye of the national selectors but also Mpongwana's ability to deliver when his team is under pressure.
In that final at Newlands, the lanky all-rounder walked to crease with the score on 81-4 in the 17th over and, together with his captain Kyle Verreynne (111), resurrected the innings.
While he says the national call-up came a bit "soon" into his professional career that started in January 2019, Mpongwana can't wait to join up with the squad.
"I am excited and I would say nervous as well. But to be honest it's surreal. Those are the words that can explain how I feel right now," he said.
"I didn't think that it would ever come this soon. When I look back I didn't think I'd be saying that in five years, I'll potentially be making my debut or in the squad for the Proteas. It's an amazing feeling."
Proteas white-ball head coach Rob Walter explained that Mpongwana's selection was to broaden the base of all-rounders in the country.
"Very excited by his inclusion. I said we need to broaden our all-rounder stocks because it does allow us to balance the team in different ways," Walter said.
"His inclusion is a reward for his performances and for us to target more all-rounders and see how we can grow them.
"It is also getting a new person into our system, (getting to understand) the way we want to play the game and our blueprint for our short formats."
The Proteas will start the India inbound tour with three T20Is from Sunday before the three-match ODI series gets underway on 17 December.