The 18-year-old is fresh from his superb performances at the Terborg Toernooi in the Netherlands, where he was crowned as the Player of the Tournament and also walked away with the Golden Boot accolade having scored 5 goals in 5 matches.
The news follows hot on the heals of Ajax’s capture of National First Division Golden Boot winner Sedwyn George from Royal Eagles.
"It feels great, awesome, very awesome. I just got back from the Netherlands and here I am signing a PSL contract – what a great feeling," said Thethani.
"What a great tournament, I learnt a lot, faced a few more challenges in getting out of my comfort zone. I have gained a lot of experience, it was a great tour.
"Yes, of course it is, massive motivation [to go back to Amsterdam]. Everything there is about football. People there are very supportive and I had a great time in the Netherlands.
"Ajax Cape Town have helped me so much, since I've arrived here I’ve picked up so much knowledge from all the coaches – things I wouldn't have learnt elsewhere, not only how to play on the field but also how to behave off it. Thank you to Ajax Cape Town.
"I have adapted very well, I have achieved a lot thus far, I hope to achieve much more," Thethani said.
The youngster joined the Ajax Cape Town’s Youth Structure in 2014, having made waves in Khayelitsha Site C where he starred for Mighty United.