The pair, along with Edinburgh stand-off Phil Godman, join the players who were part of Hadden's World Cup preparations.

Hooker Dougie Hall, who missed the tournament in France with a knee injury, is also included after making his comeback for Glasgow last week.

The 44-man squad will meet at Murrayfield for a one-day session on December 17.
Hadden said: "The consistent form of Beattie, Godman and Rennie has merited their return to the extended Scotland squad.

"The squad session will be part World Cup debrief and, as usual, will have a strength and conditioning element and a rugby element."

Godman made his first RBS 6 Nations start in the 21-9 win over Wales earlier this year.

"It's good to be back involved," the 25-year-old said.

"Obviously, missing out on the World Cup was disappointing but that's been and gone and now it's about looking forward and concentrating on playing well for Edinburgh."

Godman's Edinburgh team-mate Rennie is a graduate of the Under-18, Under-19 and Under-21 teams and has represented his country at Sevens level.

The 21-year-old said: "I'm lucky enough to have had a run of games for Edinburgh after a really good pre-season so I'm feeling quite fresh."

Beattie, 22, made his Scotland debut against Romania at Murrayfield in November last year.

The Glasgow number eight said: "It was obviously a massive disappointment not to be involved in the World Cup preparation squad but I had a pretty good pre-season and Glasgow's home record has been encouraging.

"For me and the rest of the boys just now it's about doing the day in, day out graft for the club but it's great news to have been included in the squad."