The 21-year-old Belgium international confirmed his intention to join the Blues on Monday, despite offers from Manchester United and Manchester City.
Having spoken to former teammate Joe Cole, who has played alongside Hazard at French club Lille, Lampard believes that Chelsea have added a "top player" to their ranks ahead of the new season.
"It is very exciting to hear the news. I haven't seen much French football but everyone I speak to says he is a very top player, a very top young player," Lampard told reporters.
"If he can bring that youth and hunger and ability into our team, then he'll be very welcome.
"Joe Cole knows him very well and spent a year at Lille with him. Talking about those type of players, Joe is very honest and knowledgeable and he has been very impressed with him."
Lampard was speaking just hours before suffering a thigh injury that could rule him out of England's Euro 2012 campaign.