London - Jennifer Lopez has advised Mariah Carey to "speak from the heart" on 'American Idol'.

The singer-and-actress recently departed the talent contest after two seasons as a judge and thinks her successor needs to be as honest as possible with the hopefuls on the show.

She told 'Entertainment Tonight': "So long as she's honest and speaks from the heart and just is herself, I think she'll be fine.

"I always kind of just spoke right from the heart, and how I would want someone to speak to me if I was in that position. It's just about being relaxed and being honest, and being yourself... If you try and think too much about what people might think or what you're saying too much, I think you get lost."

Meanwhile, Phillip Phillips - who won the last series of the show - hopes the new judging panel, which is rumoured to also include Nicki Minaj, will be more "critical" as he felt he was given an easy ride by Jennifer, Steven Tyler and Randy Jackson.

He told MTV News: "I would say I hope they're a little more critical. Because there were some times when I performed, especially on 'Time of the Season,' man, my ears went out, but that's live television, I can't just stop the song, so I just pushed through it as best as I could and then they gave me good feedback and I was like 'Come on guys, it was horrifying.' So, I'd like for there to be a little more criticism on the show." - Bang Showbiz