Albion boss Nigel Clough has drafted in the 19-year-old forward to add some extra firepower as League One leaders Burton - who boast a six-point advantage with nine games to go - look to strengthen their hopes of promotion.
Walker, who has made 15 senior appearances this season, had found first-team opportunities limited as of late, and Forest sanctioned his loan until the end of the 2015-16 term.
And two of his team-mates took to Twitter to send their good will.
Gardner is on loan himself, with the 23-year-old joining from Aston Villa last summer, while Burke netted his first goal for the club back in December.
Forest are currently 15th in the Championship table, nine points clear of the relegation zone but 16 adrift of the top six.
Paul Williams is currently in charge of the club in a caretaker role following the sacking of Dougie Freedman earlier this month.