Former two-weight world champion Paulie Malignaggi has offered to welcome Conor McGregor into boxing and insists he will "knock the beard off" the Irishman.
McGregor sparked rumours of a potential mega-fight with the now-retired Floyd Mayweather after being granted a boxing licence by the California State Athletic Commission on Thursday in pursuit of a "high-level opponent".
Last month McGregor, nicknamed 'the Notorious', became the first simultaneous two-weight champion in UFC history after defeating Eddie Alvarez at UFC 205 but after recently being stripped of his featherweight crown and obtaining a boxing licence, speculation of a crossover fight has grown.
But Malignaggi, who has previously held the IBF light-welterweight and WBA welterweight titles, has threatened to teach McGregor a boxing lesson for what he views as a sign of disrespect to his sport.
"I have been hearing a lot about this Conor McGregor situation and I got to thinking - you know what I am kind of interested," Malignaggi said on his Twitter account.
"At first I was telling Conor to stay in his lane and I was thinking 'you know what, you are going to embarrass yourself' but if you are really going to disrespect the sport of boxing like that then I would like to be the one to teach you that lesson.
"I would never disrespect your sport and tell everybody 'you know what, I could beat the best fighter in the cage'. You shouldn't come to our sport and tell everybody you could beat the best fighter in our sport in a ring.
"I know you apologised about absolutely nothing last fight but after I am done with you - I am going to knock the beard off you homie - you are going to be apologising for everything you have been trying to do to get into boxing."
Malignaggi last featured in a 10-round unanimous decision win over Gabriel Bracero in July.