9 October 2009, rated PG
There aren't really any famous names in this film but the main character, a young boy called Russell, is voiced by a nine-year-old called Jordan Najai.
You might also recognise the voice behind Dug the dog, who has voiced loads of other animation films like Ratatouille, Cars and Finding Nemo.
As a boy, Carl Frederickson meets adventurous Ellie and the pair dream about travelling to South America in search of a lost world. But things don't go to plan, and the couple never make it on any adventures.
Years later when Carl is a retired balloon salesman, he decides it's better late than never to live out your dreams. So with the bulldozers literally knocking at his door to make way for new houses, Carl gets loads of balloons, ties them to his house and flies to South America.
The trouble is, just before taking flight, Carl was visited by a Wilderness Explorer (basically a Scout) called Russell, who's trying to earn his final badge for helping the elderly.
Russell accidently gets swept away with Carl and the floating house! With his unwanted travel buddy, Carl and Russell head off for the adventure of a lifetime.
Along the way, the pair meet a famous explorer Charles Muntz, who's trying to trap a rare bird and take it back to civilisation. But will Carl give up his dream to help Russell save the rare bird from being captured?
This film has it all. The scenes with Carl and Russell trying to look after Kevin the bird are hilarious.
He is very mischievous and keeping him safe results in lots of funny scenes and gives the audience a chance to get to know the characters better.
The end of the film is very exciting with plenty of action, twists and turns to keep you glued to your seat. Look out for the scene at the end where the pack of dogs fly little planes! The animation is amazing, especially in 3D!
There are so many amazing characters in this film, it's impossible to pick just one. Russell, the boy who travels with Carl is hilarious and has a lot of laugh-out-loud lines. He's really relatable and he brings a lot of warmth to balance out Carl's grumpiness.
Dug the 'talking' dog is great too, he's really cute and says things that your pet dog would say if he could. For example, Dug is always distracted by squirrels, food and chasing tennis balls!
Any weak bits?
There really aren't any weak bits in this film, it goes from strength to strength.
That said it is quite a wordy film, and the action doesn't kick in until the final 30 minutes, so if it's an action-packed blockbuster you're looking for then this might not be for you.
The one thing to point out is that it is a little scary at times, so younger children may get upset during certain scenes.
Hit or miss?
HIT - UP is one of 2009's high-flyers and is sure to zoom up, up and away at the box office!
This reviews page is now closed. Here are some of the reviews you sent in.
"What a hilarious film!!! I could watch that another 10 times without getting bored of it."
Megan, 11, Surrey, England
"I thought the start was really good. But the middle and the end were boring."
Megan, 11, Surrey, England
"I loved this film. I found it a bit boring at first but I got into the story after 10 minutes. I loved it in 3D."
Kayleigh, 10, Bristol, England
"I saw it at the cinema and it was very funny, but it was also quite sad."
Emily, 10, Newcastle, England
"I think UP is a VERY good film, possibly the film of the year. It's definitely worth watching."
James, 10, Dubai, UAE
"I have seen the film and I think it's fantastic! The way they put it makes me want to see it again."
Naomi, 10, Lincolnshire, England
"I went to see UP in 3D and it was so funny I nearly fell off my seat. It was a very long film but I think it was the best film EVER!!!"
Emma, 8, Liverpool, England
"I really enjoyed UP! It was a little sad but it was really funny!!!"
Hannah, 11, UK
"It was really good but really sad as well. I was crying through most of it."
Bethany, 11, Moray, Scotland
"It was so funny it was one of the best movies I have seen. The small chubby guy made it funny and so did the Grandpa. It was just so amazing I recommend all my friends to see it. The movie was great, I loved it."
Melissa, 10, West Lothian, Scotland
"I think that UP was a great movie. The characters are really funny especially, Dug the dog. He is really good."
Jack, 11, London, England
"It was so cool I love the bird and the talking dog."
Maya, 11, Nottingham, England
"UP is AMAZING!! I saw it in May when I was on holiday in Canada and it is definitely Pixar's best film yet!"
Amy, 13, Bournemouth, England
"UP is funny and hilarious and made me laugh a lot. My favourite part was when the boy was falling down."
Jade, 7, Chesterfield, England
"I loved this film!! It was so funny I accidentally fell of my seat and everyone stared at me!!"
Maddie, 9, Oxfordshire, England
"So amazing! But so, so sad at the beginning, I even cried!"
Claire, 12, Wales
"I thought the movie was brilliant. HIT!!!"
Calum, 9, London, England
"So cool!! I saw it in 3D and it was well worth the extra money!"
Heather, 10, East Lothian, Scotland
"I really liked this movie, when I went to see it in the cinema I was laughing at loads of places."
Iain, 12, Aberdeenshire, Scotland
"I think it's really funny."
Lauren, 11, Burnley, England
"I really enjoyed this film. It was really sad but more than anything it was extremely funny."
Katherine, 11, Belfast, Northern Ireland
"Its kind of rubbish! How would that happen in real life?! They need to make it more realistic"
Shirley, 12, UK
"I saw a preview of this movie and let me tell you it was sooo funny that I literally had tears coming out of my eyes!!!! HIT!!"
Shereen, 11, Glastonbury, England
"I think this film was a bit disappointing."
Carter, 11, UK
"I saw the movie and it is was funny. I like the part when the kid found the bird."
Kathleen, 8, UK
"I went to America on holiday and I saw it there. It was fantastic for the whole family. I like the colourful balloons."
Arthur, 13, Southampton, England
"The film up is awesome. They need to make another one!"
Sonny, 12, Hull, England
"Up looks really good and one day I will go and see it in 3D."
Millie and Georgia, 10, Brighton, England
"I saw this in America. It was brilliant!! My favourite Disney movie and my favourite movie ever."
Ruadhan, 10, Scotland