The Cork middleweight will face the Canadian former IBF champion in Las Vegas at the T-Mobile Arena on Saturday September 15th.
The bout will be one of the chief supports for the WBC-WBA middleweight title rematch between Gennady Golovkin and Canelo Alvarez.
O’Sullivan [28(20)-2(1)] had long been lined up for the Golden Boy card and has been in camp throughout the Summer, training in Sardinia, at coach and manager Paschal Collins’s Celtic Warriors Gym, and his native Cork.
Last month, 29-year-old Lemieux ‘challenged’ O’Sullivan to a fight on the bill – with the Mahon man ‘accepting’. This all played out via social media but O’Sullivan would later claim that he had signed a contract. While Golden Boy president Eric Gomez subsequently discussed the fight, there were murmurs that Lemieux had yet to officially agree to the bout. Any worries, however, seem moot with tonight’s confirmation.
The fight has been described as a de-facto eliminator for the main event, with Murphys Boxing’s O’Sullivan keen to further increase his snowballing standing and get a shot at the middleweight title
Following Canelo’s withdrawal from the original rematch set for May – and his subsequent six-month drugs ban – 33-year-old O’Sullivan was involved in a protracted saga with Team Golovkin regarding him standing in. A change of terms and a new and improved contract offer from Golden Boy, however, saw him reject this offer.
The Leesider, who scored a break-out knockout win over Antoine Douglas in December, instead fought and easily defeated Berlin Abreu in California at the start of May, while Golovkin kept busy awaiting the return of Canelo with a routine defence versus Vanes Martirosyan the following night.
Three weeks later, Lemieux [39(33)-4(2)] made his return from a wide loss to WBO champion Billy Joe Saunders with a points win over Karim Achour in a bout he badly missed weight for.
Also confirmed officially for the undercard tonight were a WBO light middleweight title defence for Jaime Mungia versus Brandon Cook and a fight for former pound-for-pound number one Roman Gonzalez against Moses Fuentes. Additionally, Vergil Ortiz Jr. fights Roberto Ortiz, Alexis Rocha will face Carlos Ortiz, and Francisco Esparza will also feature.