Conor McGregor took the world of UFC by storm in 2014, and he's poised to do more of the same in the new year.

Conor McGregor Gets Into Heated Exchange With Chad Mendes Ahead of UFC 179

The former featherweight champ is slated to take on Dennis Siver on Sunday night's UFC Fight Night 59 at the TD Banknorth Garden in Boston. In anticipation of the match, McGregor appeared on ESPN2's Highly Questionable sports talk show.

Hosts Bomani Jones and Dan LeBetard got McGregor to wax philosophical on a host of subjects, from partying (McGregor calls it "a weakness for the soul") to his childhood upbringing ("two things [were important], can you play football and can you fight?"). However, McGregor saved the bulk of the time ripping his upcoming opponent.

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McGregor accused Siver of being a cheater and a steroid user, and said the only improvement Siver's made in his career is improving how to hide the substances he takes. McGregor also said he wouldn't be surprised if Siver is on PEDs when the two meet in the octagon this weekend.

McGregor's insults aren't baseless -- Siver did fail a drug test last March prior to his UFC 168 appearance.

McGregor is expected to receive a UFC title shot in his next fight should be defeat Siver on Sunday.

Watch McGregor's full interview below: