All three were formerly together at Bayern Munich.
Zirkzee told reporters after victory over Fulham on Friday: "I mean they’re two great players and we’ll see in the future what they can bring.
"I’m sure they’ll do a lot of great things here. I think Mazaroui had a great game today as well and I think De Ligt came in with a lot of good energy as well, so yeah, it’s good to have familiar faces around, but everybody in the team has been very kind and it’s top being part of this group.
"He (Mazraoui) arrived this week and it’s not easy to come into a team and play the way he did. I think it all looked natural and that was the most special part of his game today.
"But yeah, that’s just the player he is, he’s there to do his job and perform the best way he can and I think he did great today… and I'm not just saying that because he’s my friend!"