New Zealand's most-capped player admits he has always rated Shaw incredibly high but that the Lions' summer tour of South Africa reaffirmed his view that the veteran second row is among the best around.
"He's world class," Fitzpatrick, who led his country to a 2-1 series victory over the Lions in 16 years ago, told the Daily Mirror.
"I have been a fan of Simon for years.
"He's shown his true worth against some of the best locks in the world. His performances against South Africa (with the Lions) underlined that if he's fit and available you pick him."
And Shaw is now fit after a lengthy spell on the sidelines following his return from Lions duty.
The 36-year-old has been added to Martin Johnson's England squad in preparation for Saturday's clash with Fitzpatrick's countrymen, with the Wasps star tipped to start ahead of Leicester's Louis Deacon at lock.
If Shaw does start against the All Blacks at Twickenham, it would be his 53rd England cap and his 55th Test cap in total having made two international appearances for the Lions against the Springboks in June and July of this year.