Knee surgery robbed Munster of Earls' services for the first half of the season.
However, the 27-year-old played his part in the league victory over Zebre last month and, last weekend, made his first start of the campaign against Cardiff Blues, as Munster jumped to second place - two points behind pace-setters Glasgow Warriors.
Earls is set to retain his place at centre when Munster go head-to-head with mid-table Scarlets on Saturday.
And O'Mahony, who scored his second try of the GUINNESS PRO12 season in the weekend win over Cardiff, believes Earls can once again make all the difference.
"Earlsie is a different class," O'Mahony told the Limerick Leader.
"Even his presence on a field is incredible. The chat out of him, just his whole presence in general, is unbelievable.
"Defensively he is such a leader as well. Even for Ireland, you've seen him produce the goods so many times.
"Even to have him back in the squad it was a real comfort to have him there in attack and defence."
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