"I am delighted to have come to the club that I supported and used to come to see as a kid," he says.
"I have a lot of friends here and I have always kept an eye on results," he says.
"I used to come and watch Frank McAvennie and Tony Cottee when TC was the main man at the time; I don't know if I can emulate those two but I will give it a bash!"
His priority, though, is, if not to emulate Jermain Defoe, at least cushion the effect of his loss.
"Obviously Jermain is an absolute legend down here and a quality striker that I have been playing with in the England U21s - and have known for years," he says.
In fact, in a whirlwind 24 hours, he even crossed Jermain's path as he - and £7m - went the other way.
"I saw him today and wished him all the best, and he did likewise; I speak to him all the time - and no doubt will in the next day or two," he says.
"I have got a lot to live up to and I will give 110% all the time.
"I didn't get too much of an opportunity at Tottenham but I will give my all here; I didn't think I would be starting at Spurs even when Freddi Kanoute went to the African Nations' Cup though in the back of my mind I'd have hoped to.
"There are a lot of good strikers at Spurs and one or two are going to have to be on the bench and I don't know if they are going to be able to take it - but that is part of football.
"I am sure I have learned a few things at Tottenham, and when I was at Brighton I was up against it - but obviously West Ham is a strong team pushing for promotion."
Bobby's sole goal, ironically, this season, was against West Ham, and he admits to having mixed feelings about it.
"I was pleased to get my first goal but to be honest I was a bit gutted - and a lot of my friends let me know where they stood."
Bobby is confident that West Ham can rise to the promotion places and he adds:
"The lads have really started to pick up in the last couple of weeks and the new lads have been fitting in straight away and hopefully I can continue that.
"I know quite a few of the lads; I used to room with Michael Carrick with the England U21s, for instance.
"It is going to be tough getting in the side but I am going to work hard."
Emotions aside, was it a difficult move, career-wise?
"I was up late last night with my agent and my dad talking away, and it took a bit of time - but I am pleased," he says.
"I have something to prove all the time as all players do - but I will prove a few people wrong.
"But I am disappointed that I wasn't given the opportunity at Spurs; I only had five starts this season with five minutes here and there when we were losing.
"Glenn Hoddle has gone and David Pleat has come in and maybe your face doesn't fit and it is one of those things - part of football.
"But if the gaffer here gives me a chance hopefully I will show what I can do - and I can guarantee West Ham will be back in the Premiership this season or next."