The 'keeper joined the Gunners last month and many are predicting a title challenge because of it.
The 'keeper made the move across London at the end of last month having seen his playing time at Stamford Bridge seriously reduced last season as Jose Mourinho elected Thibaut Courtois as his number one.
The goalkeeping department has been an area of particular weakness for Arsene Wenger over the years, and that is why many, including Lampard, believe it is a clever move from Wenger to secure Cech.
"I think Arsenal signing Petr Cech is a big deal," he told the BBC.
"I think it's been a position that a lot of people at Arsenal, fans and friends have continuously bemoaned the fact that the keeper situation hasn't been sorted out for quite a few years.”
A potential title challenge
Most are expecting the goalkeeper to be the first of several new faces at the Emirates this summer, with it being anticipated that Wenger will push to improve his squad ahead of a potential Premier League title challenge.
That title hope comes on the back of a fine run of form in the second half of last season which saw them become the league’s in-form side, while they were also one of Europe’s most in form sides as well.
That run culminated in their second successive FA Cup triumph, and Lampard says the signing of Cech might push them that little bit further ahead in the running for the league title.
“He [Cech] will be huge for them, he might push Arsenal into the running,” he added.
“I think Arsenal weren't a million miles away last year. Year in year out they are there or thereabouts and you have to think they will put a run together."