The former United and England midfielder has answered Giggs' plea to join former team-mates Paul Scholes and Phil Neville in helping the Welshman guide last year's champions to the end of the season.
Giggs took temporary charge of first-team matters following the departure of David Moyes on Tuesday.
"It will be massive for us, a proud moment for us all," Butt told MUTV. "To be there together is a bit of a surreal thing.
"We walked in here together when we were 12 and to be here now - I'm not 40 yet but Giggsy is, and myself and Scholes are nearly there too. So for us and Phil to be there together is a very proud moment.
"We're here to try to help the club and get the results that we want from now until the end of the season. What happens after that, who knows?"
Butt is confident that all the players will be keen to see out the final four games of an inconsistent 2013/14 campaign on a positive note.
He added: "We've got some amazing players at this club, good lads who care about the club, who are really positive about United and want the best for the club.
"Saturday is a massive occasion, not only for Ryan, but for the staff, the fans and the players as well because they know that we've underachieved as a club this year.
"The players in that changing room know how good they are. They look round, look left and look right at the players next to them and know that they are very proud, hard-working lads. I'm sure we'll see that on Saturday."
Watch Giggs' first match in charge of United against Norwich on SNF Sky Sports HD1 from 17.00 on Saturday