The midfielder believes his club team-mate fully deserves international recognition and has compared him with Real Madrid's world-record signing Gareth Bale
The full-back has been called up to Roy Hodgson’s squad for the first time and could earn his maiden cap for the national team at Wembley on Wednesday.
Saints team-mate Lallana has given Shaw his full backing and believes the teenager, heavily linked with moves to Manchester United and Chelsea, merits his place in the England side.
"Luke wouldn't for one minute have thought he'd be involved in the senior team but he's an outstanding talent and one of the best, probably the best player I've ever seen at 18,” he told reporters.
“He's won plaudits and gained recognition, and he's certainly good enough to be here today.”
Southampton have seen players such as Theo Walcott, Alex Oxlade-Chamberlain and Gareth Bale come through the ranks at St Mary’s and Lallana feels Shaw is of the same pedigree.
"It's hard to compare him with the others: Gareth's gone on and never looked back,” he added.
“I know Gareth did play left-back as well, so there are similarities there, but I wouldn't want to put too much pressure on Luke. He's done unbelievably for us this season.
“When Gareth was playing with us we were in the Championship. For Luke, at 18, to be playing so consistently well for us against some of the best wingers in the world, that's credit to him and his attitude and how he keeps his feet on the ground.
“Nothing fazes him and I'm really excited to hopefully see him gets some minutes on Wednesday."