Romelu Lukaku has revealed in an exclusive interview with ESPN FC that he is delighted to be joining "the biggest club in the world" ahead of his move to Manchester United.

The Belgium international is expected to be formally unveiled as a Man United player on Monday after the Red Devils and Everton agreed to a £75 million deal on Friday.

The striker completed his medical while in Los Angeles on Saturday and is now waiting for the deal to be officially announced.

"This is an opportunity that I've always wanted since I was a child," Lukaku told ESPN FC's Alexis Nunes.

"When [Manchester United] came calling, I didn't have to think twice. So I'm really delighted to hopefully be part of their history."

Lukaku, 24, has been the subject of intense transfer speculation since April, when he confirmed that he would not extend his contract with Everton.

His former employers Chelsea were reportedly interested in the striker, and even tabled a late offer to try and convince Lukaku to move back to Stamford Bridge. The Belgian, however, had already made his mind up.

"My mind was already set. I gave my word, and I don't look back," Lukaku said. "I didn't look back since, and I was already mentally preparing to be part of the team."

When asked what he would tell people who queried why he chose Manchester United -- who came sixth in the Premier League last season -- over the champions, Lukaku responded: "I would say, 'Who would say no to the biggest club in the world?'

"Best stadium in England. The best fans. This is the perfect opportunity. I always said I wanted to play for a team that's challenging for every trophy that there is.

"I think Manchester United at the minute wants to be the dominant team, that dominant force. If you look at their history, it says enough. To become part of a club like them is something that I really wanted. I'm thankful for the opportunity that they gave me.

"Now it's time to work hard, work harder than I ever did before. I'm willing to do it. Hopefully, it will come a good way."

Lukaku's soon-to-be Manchester United teammate Paul Pogba is also in LA with on vacation and the duo took some time out to take on all comers in a 5-a-side match at the Urban Soccer 5 centre. Now, Lukaku can't wait to line-up alongside the French superstar in the Premier League.

"I've been talking to [Pogba] for about seven or eight years. And now he's living in Manchester," Lukaku explained. "I live in Manchester. He lives like down the road from where I live, so we're together on a daily basis.

"He was explaining to me how it went at the club, and it triggered something in my head. When the opportunity came, I didn't have to think twice. I'm really excited.

"All of [the Man United players]. I think they're all top players, a good group of guys that is hungry to win trophies.

"And to play in front of those fans, everything is set there to perform. But, you know, I have to work harder than I'm doing now. I know the road is still far, but I'm willing to go on that path and grab the opportunity that I get."

Lukaku also spoke about his desire to once again work with Manchester United manager Jose Mourinho. The pair were previously together at Chelsea but, after a succession of loans, Mourinho was the one that sanctioned Chelsea's sale of Lukaku to Everton three years ago.

The 24-year-old, however, has only praise for his prospective new boss, labeling the Portuguese as "the best manager in the world."

"[Mourinho is] a guy who I wanted to play for since I was 10 years old, so now to have the opportunity to work under him again is great," Lukaku said.

"We've been in contact. He explained to me how the club was like, what he expects from me.

"You know, we were together under different circumstances. Obviously, the first time when I met him, I was still a young kid, and I was eager to play. And he understood my decision why I left at the time. I returned on the pitch.

"Now I'm 24. I'm a grown man. He sees the maturity that has grown throughout the years, so I'm really thankful for the opportunity he gave me again."

Lukaku scored 71 goals in 133 games for Everton since signing permanently in 2014. The striker now wants to work with Mourinho and help convert that impressive record into silverware.

"I think he wants to improve me, make me a better player than I am today, which is good. I always want to improve," Lukaku said.

"I always want to work on the good stuff, but also the bad stuff. He knows how to make players better, and make from players winners as well.

"For me, I think it's the perfect opportunity. I'm 24. I never won a major trophy, but I'm eager to win something and to be part of a team that wins trophies, and I think he's the right guy to help me in that."

http://www.espn.co.uk/football/manchester-united/story/3155160/romelu-lukaku-opens-up-about-his-move-to-man-united-jose-mourinho