Abdul appeared on the judging panel for the show's first season but confirmed in January that she would not be returning.
Earlier this month, Fox confirmed that Spears and Lovato will take the spots vacated by Abdul and her fellow former judge Nicole Scherzinger.
"I think they're going to be fantastic," Abdul told E! News, adding that she thinks both Spears and Lovato are "sweet".
Abdul, who said that she is a "fan" of The X Factor, also offered the duo some advice for appearing on live television, saying: "You have to go with the flow, speak your mind, and just remember millions of people are watching."
Lovato and Spears joined Simon Cowell and LA Reid in Austin, TX for the first auditions of the new season yesterday. Spears later denied rumours that she had "walked out" of the auditions.
Scherzinger has also offered her support to Spears and Lovato, saying that she is "rooting" for them.
The X Factor will return to Fox in the fall.
Photo gallery - Judges arrive for the X Factor auditions in Texas: