But despite moving a small step closer to fulfilling his dream of becoming a professional footballer, Dondre told his local paper, The Haringey Independent, he felt "a bit guilty” because he was once a fan of the North Londoners.
He said: “I’m really excited to be training with West Ham. I have just started and it has been really hard work so far.
"I like being a keeper because I get to use my hands and dive. My favourite match was against West Brom where I did lots of top corner saves.”
The hot prospect has already fallen for the claret and blue and hopes to follow in the footsteps of his West Ham idols, fellow goalkeeper and Hammers cult hero Adrian and striker Andy Carroll.
Although Sam Allardyce has been reluctant to give youth a chance at West Ham until recently, it is unlikely the Hammers boss will be the manager at Upton Park next season let alone if Dondre makes it as a professional in a few years' time.
But history says he couldn't be at a better club with the Hammers famous for their youth production line having brought through a long list of players all the way to the England senior team over the years.
Most recently Mark Noble, James Tomkins and Reece Burke have made the jump from the self-styled 'Academy of Football' while other famous names include World Cup winning captain Bobby Moore, Sir Trevor Brooking, Rio Ferdinand, Frank Lampard, John Terry, Joe Cole, Glen Johnson, Jermaine Defoe and Michael Carrick.
The last goalkeeper to graduate from the Academy ranks to the Hammers first team was Stephen Bywater, then 19, who now plays for Doncaster Rovers aged 33.
If Dondre wants to become West Ham's youngest ever player he will have to make his debut not long after his 17th birthday to beat the record set by Neil Finn on New Year's Day at Manchester City in 1996 when he was 17 years and two days old. After Finn, Cole and Ferdinand are the club's next youngest ever first team stars.