O’Neill managed Celtic from 2000-05, winning three Scottish Premier League titles, three Scottish Cups, and a League Cup. He also took the club to a Uefa Cup final.
However, he has not managed a club since he being sacked by Nottingham Forest in June 2019 – more than six years ago.
Coincidentally, the former Republic of Ireland manager was on TalkSport earlier on Monday taking about the Scottish title race – and his belief that Hearts could become the first non-Old Firm side to win it since 1985.
“Hearts have shown a great determination. Their record is great, at this minute,” O’Neill said. “With Celtic not being as strong, as physically as strong, as maybe you would want them to be. It is possible.
“Celtic can actually lose games now, whereas before, they looked invincible in matches. Rangers are no threat whatsoever. They are so far adrift it’s untrue.
“But this is the moment, this is the time for Hearts. They have gone eight points clear. That is a decent enough lead, really. Their confidence has grown, and it will grow from that victory.”
O’Neill will be joined by Maloney, who had two spells as a player with Celtic and was part of Belgium’s coaching staff for a stint after retiring.
The Scotland international took on his first job with Hibs in 2021 but lasted just four months.
Then he took charge of Wigan Athletic in January 2023 but was dismissed in March of this year, having won 42 of his 115 games in charge.