It is the third time the Dutchman has worked with his compatriot after spells together at PSV Eindhoven and AZ Alkmaar.
Advocaat was due to leave Wearside at the end of last season before having a change of heart and eventually signing a one-year deal.
Lens, who arrived from Dynamo Kiev for £8.5m, will get his first taste of English football this weekend as Sunderland start their Premier League campaign away to Leicester City.
“It’s easy to have a Dutch coach, it is easy to have a Dutch team player and I’m looking forward to the beginning of the season,” Lens said.
“I know when he (Advocaat) came to Sunderland it was only for a few games last season so I didn’t know he would sign for one more year.
“But when he did decide to sign for one more year I spoke with him and I had a good feeling with him about Sunderland and that’s where the process started for the transfer.
“He knows what my qualities are and I know what he expects from me. Everything is clear.”
Lens also praised new signing Yann M’Vila, who joined the club on a season-long loan from Rubin Kazan.
“He trained yesterday, he trained today and my first impression is that he is a good player,” Lens said.
“He’s a control midfielder and he is always looking forward and that’s what we need because I am a forward player and I like to play with the space behind the defenders, so it is important that when we get the ball we play as soon as possible to the strikers and he’s a player who can do that.”