He said the event this weekend has the "best-ever" line-up, featuring bands ranging from One Direction to the likes of Katy Perry, Kings of Leon, Coldplay and Bastille.
Up to 50,000 revellers will attend the festival on Glasgow Green on Saturday May 24 and Sunday May 25.
A further 14,000 tickets for an additional dance event on May 23 have also been given away.
Radio 1 DJs Annie Mac, Pete Tong, Zane Lowe and Danny Howard will all star in the George Square party to kick-start the weekend.
James, who hosts the 4pm-7pm Radio 1 show every weekday, said: "I really believe this is the best one ever for my tastes.
"Coldplay are my favourite-ever band and Katy Perry is my pop star crush, so it's the best ever.
"Scottish crowds are always the most rowdy, they just love it when a big event comes into town, so with the Friday and the weekend nights it's just going to be a big party."
He added: "It's one of those great line-ups that reflect everything we play. It's so diverse. You've got Jake Bugg and One Direction on the same stage, that doesn't really happen anywhere else."
Coldplay are the headline act on Saturday while One Direction, Calvin Harris, Bastille, Pharrell, Jake Bugg, Lily Allen and Ed Sheeran will also perform that day.
Kings of Leon, The Vamps, John Newman, Rita Ora, The 1975, Tinie Tempah and Paolo Nutini will all perform on the Sunday, with Perry closing the festival.
Radio 1 controller Ben Cooper previously said: ''It's a phenomenal line-up, probably the best in the world this year, in one of the world's great music cities.''
A total of 50,000 for the festival were snapped up in just over half-an-hour in March.
Radio 1 DJ Nick Grimshaw is hosting his breakfast show from Glasgow this week in the run-up to the Big Weekend.