Liverpool manager Jurgen Klopp has described England midfielder Jude Bellingham as "exceptional".
Bellingham has repeatedly been linked with a big-money move to Liverpool and European champions Real Madrid.
"I don't like to talk about money when you talk about a player like him," said Klopp before Liverpool's away match against Aston Villa on Monday.
"Everyone can see he is just exceptional."
Bellingham moved to Dortmund from Birmingham City aged 17 in 2020 and has captained the Bundesliga side this season.
He made his World Cup debut in Qatar, scoring in England's opening 6-2 win against Iran and was one of his team's standout performers at the tournament.
Klopp, who had a seven-year spell as Dortmund manager before joining Liverpool in 2015, added: "If you mention to someone who has no clue about football, or who knows about football and has not watched it for a while (and ask) 'How old do you think Jude Bellingham is?', I don't think anyone would get even close to his age.
"They would say 28 or 29 because he plays so mature. He played an exceptional World Cup. Absolutely exceptional.
"With all the things he has and things he can improve, to describe him I would say the things he can do are difficult to learn, and the things he can improve are easy to learn.
"So, yes, he is a really good player. What can I say? I have thought that already for two or three years since he had his breakthrough at Dortmund.
"Everybody knew already but I have no idea what that means for the money side of it.
"I really think if we all want to do him a favour then we do not talk too much about money. I mean that from an England point of view. Do not throw any hurdles in his development."
Liverpool are sixth in the Premier League, seven points behind fourth-placed Tottenham, with a game in hand.
Klopp said ensuring Champions League football was the "main target" for the club this season.