4:10 PM PT -- A rep for Jerry West tells TMZ Sports he did nothing improper ... and didn't even know he was being sued.
“I am not aware of any lawsuit being filed against me and I deny engaging in any improper conduct in connection with the signing of Kawhi Leonard.”
A man who claims to be Kawhi Leonard's pal says Jerry Westowes him $2.5 MIL for his role in helping the Clippers land the NBA superstar ... and he's demanding JW pay up ASAP.
It's all in a new lawsuit obtained by TMZ Sports ... in which Johnny Wilkes spells out how he agreed to work with West for a small fortune in exchange for help getting Kawhi in a Clippers uni.
Wilkes says back on April 10, 2019, he met West at Staples Center and informed the Clippers' executive board member he had close ties to Kawhi and Kawhi's uncle, Dennis Robertson.
Wilkes says he and West exchanged contact information ... and a few weeks later, in June, West asked Wilkes for help in courting Kawhi to Los Angeles.
In the suit, Wilkes claims he told West he'd only help if the Clippers would pay him $2.5 MILLION ... and Wilkes claims West agreed to the terms.
Wilkes says in the lawsuit he "immediately went to work" ... and began convincing Kawhi and Kawhi's uncle the Clippers were the right team for him after he had just left the Toronto Raptors.
Wilkes says he told West and the Clippers they needed to get Paul Georgefirst and foremost to hook Kawhi. He then says he helped connect West with Kawhi's uncle.
Wilkes also claims in the suit he gave West a specific gameplan for how the Clippers should pitch Kawhi during an important meeting with West, Leonard, Doc Rivers and others in July 2019.
"This information was vital," Wilkes said in the lawsuit, "because it was the exact information Kawhi Leonard wanted to hear at the time in order to effectuate his signing with the Clippers."
Wilkes also says he helped facilitate a deal between West and Kawhi's uncle ... in which West agreed to give Uncle Dennis a Southern California home and a travel expense account.
Wilkes says after Kawhi ultimately agreed to sign with the Clippers in late July ... he went for a celebratory meal with West and others in Beverly Hills.
Wilkes claims West agreed yet again at the dinner to fork over $2.5 million for all the help ... but Wilkes claims in the suit he still hasn't received a penny -- and he's suing West and the Clippers for breach of contract and more.
Wilkes is asking for the $2.5 mil plus damages.
We've reached out to the Clippers for comment ... but so far, no word back.