'Who would say no to the biggest club in the world?'

Romelu Lukaku said he was delighted to be moving to "the biggest club in the world" after Manchester United agreed a fee to sign the Belgium international striker from Everton.

British media reported that the fee for the 24-year-old would be around 75 million pounds, making him the club's second most expensive signing after last year's world record deal for French midfielder Paul Pogba.

"Who would say no to the biggest club in the world," Lukaku told ESPN. "When [Manchester United] came calling, I didn't have to think twice. So I'm really delighted to hopefully be part of their history.

"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."

United are hoping to confirm the deal before they depart for a pre-season tour to the United States on Sunday.

"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 on vacation and the duo are very close. Lukaku said that he cannot wait to line up alongside the France midfielder in the Premier League.

"I've been talking to [Pogba] for about seven or eight years. And now he's living in Manchester," Lukaku said. "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.

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, labelling the Portuguese coach 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."

"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."