The pound-for-pound fighter is scheduled to fight Ortiz on September 17, his first bout for 16 months.
Mayweather knows only too well the passion British fans show to the sport when he fought Ricky Hatton in 2007.
Mayweather could eventually face Khan should the Bolton fighter overcome Zab Judah on Saturday.
WBA light-welterweight champion Khan meets IBF king Zab Judah in a unification fight before a likely move up to welterweight where he could face Floyd Mayweather.
"I have so much love for my fans in the UK," said Mayweather.
"Ever since I fought Ricky Hatton in 2008 and then held an open workout in London in 2009, they have shown me nothing but support.
"I wanted to do something for them and I hope they can attend my work-out."
