An ambassador for Laureus Sport for Good, Shevchenko surprised children who had fled the war with a visit to a school in Warsaw.
The world has rallied around Ukraine following Russia's invasion, with sporting stars and celebrities using their platform to raise awareness of the situation in the country.
On Saturday, WTA world number one Swiatek organised a charity tennis match, where Shevchenko was a special guest, while Lewandowski has been vocal in his support – and will wear a Barcelona shirt featuring the UNHCR logo, the United Nations' main agency for refugees, this season.
Following his appearance in Warsaw, Shevchenko thanked Poland as a nation for taking in a flood of refugees from their European neighbours.
"I want to thank you, [the] Polish people, for being very kind to my country. For hosting us here. For providing all the needs," he said, as per Laureus Sport for Good.
"Thank you so much for your support. Also, I want to thank Iga Swiatek and Robert Lewandowski for taking a big part in initiatives helping my country to raise the funds and support against the war in Ukraine."
Shevchenko also praised compatriot Oleksandr Zinchenko for speaking out against the war, something numerous Ukrainian athletes have done.
"Like many, everyone Ukrainian, his reaction against the war, he stood up and then he spoke loud," he added of Zinchenko, who last week signed for Arsenal from Premier League champions Manchester City.
"He expressed his view, he's expressed his very hard feelings against the war for Ukraine, because he loves Ukraine, he loves people.
"And we did a lot of activities together, we've been involved in a few fundraisers. I know he's a very generous person and he did a lot for Ukrainian people."
Zinchenko played a key role as Ukraine defeated Scotland 3-1 on Wednesday at Hampden Park in an emotional return to competitive action.
The World Cup qualifying play-off semi-final was delayed from March following Russia's invasion of Ukraine, which is still ongoing.
But goals from Andriy Yarmolenko, Raman Yaremchuk and Artem Dovbyk mean that only Wales stand in the way of Ukraine and a place in Qatar.
Manchester City utility man Zinchenko, though, knows the requirements are clear heading to Cardiff for Sunday's contest.
"Everyone knows the situation right now in Ukraine and every single game is like a final for us," he told Sky Sports.
"We have dreamed to be at the World Cup, so we have one more game, one more final and we need to win it, otherwise this game is not going to mean anything.
"It's going to be a massive game for us. Everyone understands the situation. Every one of us needs to show the best performance in our lives and then we'll see what's going to happen."
In his post-match news conference, Ukraine coach Oleksandr Petrakov said: "I have no emotion, I left my emotion on the pitch. This wasn't a win for us, it was for our country."
Ruslan Malinovskyi, the Atalanta midfielder, told beIN SPORTS: "This win for our people, our country, in a difficult period they are living.
"Also my parents, my brother, they are there in Ukraine and we just want it to finish and pray for our people that this war is finished as soon as possible.
"Now we are not playing for ourselves, we play for our whole country. Soldiers, also normal people, will follow [the Wales] game with their phone, on their TV.
"I think it will be a similar game. It will be a battle, the same, we need to play our game, be fast and be ready for the duels."
Russia began invading neighbouring Ukraine over a week ago after rising political tensions between the two countries.
The attacks were greeted by widespread condemnation, with sporting, political and financial sanctions imposed on Russia in an attempt to deter their efforts.
Russia have been banned from competing in the men's 2022 World Cup and women's European Championship, while St Petersburg was stripped of this season's Champions League final.
In an act of solidarity, Zinchenko was named captain for Manchester City's FA Cup tie at Peterborough on Tuesday and the left-back has thanked the world for showing support.
"I'm so grateful," he told BBC Sport. "I'm so grateful to all these people for the support I'm getting here. I didn't realise it's going to be like that in this way. So I would like to say all of them big thanks. I appreciate it.
"I'm getting a lot of messages from a lot of guys in Ukraine and they are asking me about the videos of support [from the UK]. So people are watching TV, the people are still watching football, and they can see all these things, and I guess it helps a lot for them."
Zinchenko's torment continues around the clock, as he pointed to starvation in his homeland and the prospect of many having to live in bunkers, hoping to survive.
"I'm just crying," he said. "So already a week, I'm not counting, but even I can drive the car from the training ground, or it doesn't matter where, I can just cry from nothing.
"It's everything in my head. Imagine the place where you was born, where you was growing up. And there is just empty ground."
Zinchenko said he wanted to send a message that nobody should forget the plight of Ukrainians.
"We need to stop the war," he added.
The 25-year-old explained his intention to inform the world of what is going on in his homeland.
"I spoke with many people who are on our side. And they said that the way Russian TV is showing us is ridiculous," he said. "My mission is to show the rest of the world what's going on in this moment.
"There are few cities in the lowest part of Ukraine where the civilians, Russian people, are coming, and they do fake protests that like 'we want to be with Russia' and stuff like that. I can show you one million pictures. I can show you one million videos, what they are doing now. I can show you every city in my country, which they destroyed."
Zinchenko lifted the Premier League title with Manchester City earlier in May, three months after Russia invaded neighbouring Ukraine following heightening political tensions between the two countries.
The 25-year-old dedicated the English top-flight triumph to the people from his homeland, and will now look to deliver more success for Ukraine when they face Scotland in the World Cup play-offs.
The delayed play-off match on Wednesday will mark Ukraine's first outing since the Russia conflict began, with the winner of the game with Scotland facing Wales for a spot in Qatar.
Zinchenko was reduced to tears as he addressed a news conference on Tuesday, detailing his desire to make Ukraine proud once more.
"Every Ukrainian wants one thing – to stop this war," he said.
"I spoke to people from different countries, all over the world and I spoke to some Ukrainian kids who just don't understand what's happening back in Ukraine.
"They only want the war to stop. They have one dream to stop the war.
"When it comes to football, the team, we have our own dream. We want to go to the World Cup, want to give these incredible emotions to the Ukrainians because they deserve it so much at this very moment."
Hampden Park will host the play-off match and the Scotland supporters will be provided with a translated version, provided by language learning app Duolingo, of the Ukrainian national anthem to show their support.
Zinchenko was quick to thank Scotland for their warm welcome in Glasgow, as he suggested the conflict in Ukraine could happen to any country.
"I would like to say as well that a lot of countries maybe don't understand that – today it is Ukraine but tomorrow it can be you," he added.
"So that's why we need to be united and need to defeat aggression altogether. I am sure that the whole of Ukraine will be watching us. We will feel the support.
"We can talk a lot, but we need to prove everything on the field. We will try to make our people happy and proud."
Shakhtar Donetsk and Metalist 1925 played on Tuesday to mark the first official game played in Ukraine since Russia's invasion six months ago.
Following that 0-0 draw, three additional fixtures took place and another two were initially scheduled for Wednesday
Football in Ukraine is not fully back to normal, however, with all matches played behind closed doors in the capital Kyiv or the west of the country, while air-raid sirens will also be used in the event of potential danger.
Sirens were heard on multiple occasions during the suspended match between Rukh Vynnyky and Metalist Kharkiv on Wednesday, Ukraine's Independence Day.
Despite the risks, Zinchenko believes allowing football to resume is a step in the right direction and can boost morale in a country that has been under siege for half a year.
"It's important for the country and all Ukrainian people because nobody was ready for this situation," he told Arsenal's official website.
"People are still suffering and we need to fight every single day everywhere, but we need to keep going, live our lives and carry on.
"People deserve the lives they had before. I'd like to say a massive thanks to the Ukrainian Federation, and president [Volodymyr] Zelenskyy who said we needed to play our competition in Ukraine.
"I know it's not going to have the best facilities, but we need to keep going and that's the most important thing for all Ukrainians. I can't wait and I'll watch all the games if it's possible.
"It's difficult for me to imagine how it's going to be. There could be a siren and the players need to stop at some point, but it's so important to show the rest of the world that the Ukrainian people don't give up, and in any situation, they carry on. It's all about our people."
