Bull has not played first-team football this season

Glovers boss Gary Johnson made his move for the 22-year-old after seeing the Glovers lose their last three games and concede eight goals.

"I'm always happy when a good new player arrives at Huish Park," said Johnson.

"Ronnie has definitely got the right mentality for our team and is a player I have been following for some time, so I was delighted when he became available.

"He will add some tough tackling and aggression to the side at a time when we need it," the Yeovil boss told his club's website.

Bull has made 50 league appearances for Millwall since coming through the youth-team ranks, but his not figured so far this season.