The eight previous Lions in the squad are Shane Williams, Ronan O'Gara, Andrew Sheridan, Simon Shaw, Paul O'Connell, Martyn Williams, Phil Vickery and Stephen Jones. They have 546 international appearances between them.
"I think it is really exciting that we have a lot of players making their debuts. I remember my debut against Western Transvaal at Potchefstroom in 1974 and it is a career highlight," said Lions head coach Ian McGeechan.
"For young men such as Keith Earls and Jamie Roberts it will be a day to remember and they will be thrilled to get an early taste of match action on the tour. Outside these guys is the proven experienced combination of the Ospreys' back three of Byrne, Bowe and Shane Williams.
"While we have a lot of players making their Lions debuts there is a huge amount of international experience in the team. The average age is 28 and that reflects the maturity we have in the squad.
"On Saturday, we have in the team Martyn Williams, Ronan O'Gara and Simon Shaw who are on their third Lions tour. They know exactly what is in store in terms of the provincial matches.
"Scottish captain Mike Blair is at scrum-half while players of the calibre of Paul O'Connell, Joe Worsley and Adam Jones have played over 50 Tests each.
"Following excellent preparation and a period of acclimatisation in South Africa I know the lads are raring to go on Saturday against the Royal XV and will be anxious to get the tour off to the best possible start."
Lions tour manager Gerald Davies announced the team at the Sandton Sun hotel in Johannesburg today. Like McGeechan, he also made his Lions debut in South Africa, back in 1968.
"After all the preparation, the match against the Royal XV on Saturday marks the start of the 2009 tour. Everyone in the tour party is looking forward to getting the playing part of the tour underway," said Davies.
British & Irish Lions vs Royal XV
15. Lee Byrne (Ospreys/Wales)
14. Tommy Bowe (Ospreys/Ireland)
13. Keith Earls (Munster/Ireland)
12. Jamie Roberts (Cardiff Blues/Wales)
11. Shane Williams (Ospreys/Wales)
10. Ronan O'Gara (Munster/Ireland)
9. Mike Blair (Edinburgh/Scotland)
8. Andy Powell (Cardiff Blues/Wales)
7. Martyn Williams (Cardiff Blues/Wales)
6. Joe Worsley (London Wasps/England)
5. Paul O'Connell (Munster/Ireland) captain
4. Simon Shaw (London Wasps/England)
3. Adam Jones (Ospreys/Wales)
2. Matthew Rees (Scarlets/Wales)
1. Andrew Sheridan (Sales Sharks/England)
16. Lee Mears (Bath/England)
17. Phil Vickery (London Wasps/England)
18. Alun-Wyn Jones (Ospreys/Wales)
19. Stephen Ferris (Ulster/Ireland)
20. Mike Phillips (Ospreys/Wales)
21. Stephen Jones (Scarlets/Wales)
22. Riki Flutey (London Wasps/England)