Young and Walker developed a close bond when they played together at Aston Villa, with Walker's support from full-back helping Young put in the kind of performances that caused United to pay big money for his signature in June.
Walker's time at Aston Villa has also paid dividends for him. The 21-year-old spent the second half of last season on loan at the Midlands club, where his impressive displays helped him become a regular member of the England squad.
Now back at Spurs, Walker is battling with Vedran Corluka to become Harry Redknapp's first-choice right-back, and he seems to be ahead of the Croatian after starting against Hearts on Thursday in the Europa League.
Walker has tipped Young to become a star with Sir Alex Ferguson's side, but will do everything he can to shackle the winger when the two come face to face in Monday night's evening kick-off at Old Trafford.
"It didn't surprise me when he moved to Man Utd. You can see from what he did last year at Villa that he is a quality player," Walker said.
"All the best to him. I'm actually glad he got the move.
"We get on really well, me and Ash. We had a good understanding at Villa. We still talk off the pitch, which is nice, but I'll just treat it as a normal game and I'll look forward to coming up against him.
"When you cross that white line it's a game of football and I need to do a job out there."
Thursday's Europa League play-off hammering against Hearts was not only a morale boost for Redknapp's side, but it also gives the Spurs boss a chance to rest most of his first team for the return leg on Thursday at White Hart Lane.
The club's opening four fixtures include games against both Manchester teams and Liverpool, but Walker is confident the players will be able to cope.
"It's a tough few games for us," the defender said. "We are more than capable of rising to the challenge though."
Tottenham captain Michael Dawson is not worried that the postponed match against Everton will impact on Monday's performance.
"Hearts had a lot more games than us and we went up there and gave a good performance," Dawson said.
"It will be more or less the same team on Monday and we are ready for Man United now. We're looking forward to it."
Dawson is determined for Tottenham to claim a top-four spot this season after missing a large chunk of the club's Champions League campaign last term through injury.
Redknapp thinks he will need at least two new additions to his squad to make that happen though, and Dawson hopes deals for the likes of Emmanuel Adebayor and Lassana Diarra are concluded soon.
"Adebayor is a top player," Dawson added. "We have been linked with a number of top players and whoever comes in will improve the squad.
"New signings always help. We have a fantastic squad but to try and improve and go to that next step you always have to bring in a few new players to freshen things up."
Hanging on to Chelsea target Luka Modric will be arguably as important as bringing in any new players.
Dawson has been vocal in his support for Spurs chairman Daniel Levy, who says the player is not for sale at any price, and the skipper reiterated his support for the 49-year-old.
"You want to keep your best players. The chairman has said before that he wants him to stay here and let's hope he does," Dawson said.
"The lads want him to stay here so we will see what happens."