Borussia Dortmund forward Sancho, 18, has been called up for Nations League games in Croatia on Friday and Spain next Monday.
He has started just once in the Bundesliga for Dortmund this season, but has registered six assists and scored once.
Everton’s Walcott was just 17 when he was a surprise pick for the 2006 World Cup – although he did not play in Germany – having not made a senior appearance for Arsenal at the time.
Based on his experience, the forward believes Sancho can perform.
“He can deal with it, he’s been in the Dortmund dressing room, he’s played at their stadium, which is fantastic,” said Walcott, who has 47 England caps. “He won’t be fazed at all.
“It’s completely different now, there are a lot of young players in that group. When I came through there was Frank Lampard, Steven Gerrard – completely established players in the team – so it’s a different environment I would say.
“Of course it’s still daunting, but when you get down on the field and play football that’s all you want to do, you just want to play, it doesn’t matter who it’s for.
“You just want to go out there and do your best and I’m sure everyone will.
“The young players with England is fantastic to see and they’ve just got to take their chances. Good luck to them all.”
Walcott has not played for England since November 2016 and confirmed he did not speak to manager Gareth Southgate before his squad was announced last week.
Leicester’s Ben Chilwell was last night called into the England squad as a replacement for injured Manchester United full-back Luke Shaw.
Chilwell, who made his Three Lions debut as a substitute in the 1-0 friendly win over Switzerland at the King Power Stadium last month, had originally been included in the Under-21 squad.
But the 21-year-old will now take the place of left-back Shaw –who will miss the Nations League double-header against Croatia and Spain – in Southgate’s senior ranks.
England, meanwhile, will wear the Football Foundation’s logo on their shirts for the forthcoming double-header against Croatia and Spain.
The Football Foundation, the UK’s largest sports charity, was set up in 2000 by the Football Association, Premier League and Sport England to invest in grassroots facilities.
The timing of the link-up is hugely significant as the Football Foundation would have a crucial role in deciding how any windfall from the proposed sale of Wembley would be spent.
Fulham owner Shahid Khan has offered the FA £600m in cash and £300m in retained revenues for the stadium and that deal has been inching closer to completion over the last six months.
The American billionaire hopes to relocate his NFL gridiron team Jacksonville Jaguars to London, while the FA want to use the money to transform the country’s increasingly-stretched community facilities.
Under the terms of the deal the stadium would continue to stage all the football and rugby league games it currently hosts, apart from England’s home internationals in September and November as they clash with the NFL season.
Khan would also be prevented from renaming Wembley, have to maintain the venue as a world-class football stadium and the FA would get a share of any profit he made on a future sale.
But despite these safeguards there are some in the game who see the sale as another example of a national asset being sold abroad, while others believe there are better ways to fund grass-roots facilities.
Those points of view are likely to be aired at what promises to be a lively meeting of the FA Council on Thursday, the day before England’s game in Croatia.
Selling Wembley is ultimately a decision for the FA Board, but the national governing body’s leadership have always said they would not proceed without a broad consensus to do so, which means winning over a clear majority in the 127-strong council.
Last month FA chairman Greg Clarke and chief executive Martin Glenn had hoped to secure the board’s unanimous backing, but had to settle for an agreement to continue discussions, first with the council and then back at board level.
Last week the FA invited coaches, fans, parents, players and volunteers to take part in their annual survey of the grass-roots scene.
In a statement Glenn said the survey helped the FA “shape and improve our decision-making processes” across the grass-roots game.
“Community football facilities are the perfect example,” he said.
“Despite a number of excellent programmes in place, feedback from previous surveys has repeatedly shown many are inadequate and require further investment.
“Whilst happy with the availability of grass pitches, participants generally report they are of poor quality.
“This key information from within the game allows us to prioritise development and resources in these areas.”
Since its creation, the Football Foundation has invested £1.5bn in facilities, including 700 all-weather pitches, 1,000 changing pavilions and 4,000 grass pitches.