Lillis told BBC Radio Lancashire: "He's a great addition. It's something we've discussed for some time, myself and [manager] Sammy McIlroy.
"He is a born leader and very respected in the dressing room. He will be a great help to me."
The 34-year-old has been at Morecambe since his move from Telford in 2002, making over 300 appearances and had a brief spell in charge of the first team following former manager Jim Harvey's heart attack in 2005.
Lillis said: "We'll be able to split the squad up. I can work with the forwards and Jim might take the back four so it's going to be a big help to everyone."
Lillis has said that the coaching role will not see an end to Bentley's playing career.
"When we told him the first thing he said to me was 'I'm still playing, you know'. If he's doing well and producing the goods then he'll be in the team," He added.
Source: BBC Sport
Source: BBC Sport