Buttler had said getting a recall to England's Test squad feels as if he had been given "another debut".
Buttler played the last of his 18 Tests in December 2016, against India in Chennai.
But despite becoming a white-ball specialist in the intervening 18 months, he has been included in England's squad for the first Test against Pakistan at Lord's starting Thursday.
It is Buttler's form in the Twenty20 Indian Premier League, rather than English cricket's first-class County Championship that has propelled him back into the Test arena following a run of five successive fifties, including two unbeaten 90s, for the Rajasthan Royals.
Now he is set to bat at number seven in the first of a two-Test series against Pakistan.
"It's a fantastic surprise and an incredible opportunity afforded to me," Buttler told reporters at Lord's on Monday.
"Any time you turn up here at Lord's it's special, and all of those emotions are arriving today. It feels like another debut really," he added.
"It wasn't particularly on my radar."
"To get that call the overriding emotion was excitement...Turning up here on England duty to play a Test match is unbelievable."
- 'Pinnacle' -
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"Virat signing for Surrey to get used to playing in England, to play well in Tests, shows that in the forefront of players' minds, Tests are still the pinnacle."