The latter moved to Arsenal in the summer, but Lallana believes their competition for the right-back slot at St Mary's last season has led to these call-ups.
"Those two last season were kind of fighting it out at right-back," he said. "It did them both the world of good, I think, having that competition there.
"They've both come on to be top right-backs and they're both very young. It is very promising for England.
"You always knew that Calum and Clyney were forever improving. It was only a matter of time before they got the call."
For the big stories and the banter follow us on Twitter: @tribalfootball