Cuthbert was one of four Blues players chosen by Gatland on Tuesday. Sam Warburton will lead the Lions while Leigh Halfpenny and centre Jamie Roberts are also on the plane. None of those three are involved at Ravenhill though, Cuthbert the only starter of the Lions' contingent.
"That England game was big for everyone," said Cuthbert.
"Warren had seen what I could do but I put my hand up a little more. It couldn't have worked out any better for us. It was a shame I couldn't play again until now but I guess I did enough.
"It's mad how far I've come in rugby really - it's hard to explain. Obviously playing the last two years as a professional is a short period of time in which so much has happened and this tops it off.
"It's exciting to go out there and prepare. Playing Australia, they're one of the best teams in the world and we've got bad experiences from being out there and losing closely.
"But the team and the Lions squad that are going out there will hopefully be able to do a job."
While looking forward to Australia, Cuthbert will first be looking to prove his fitness against the PRO12 leaders.
He starts on the right wing tonight with Dan Fish and Harry Robinson joining him in the back three. Rhys Patchell and Harry Robinson, who has been selected in Wales' training squad for the summer tour of Japan, also start.
In the forwards Michael Paterson, playing his last game for the Blues before joining Sale Sharks, starts at No. 8.
Josh Navidi, Lou Reed, Bradley Davies and Scott Andrews, who are all included in the 32-man training squad for Japan, are also involved.
While the Blues have little to play for in their final game of the season, it's a vital 80 minutes for Cuthbert in terms of match fitness.
And opponents Ulster know a home win would secure a home semi-final, most probably against the Scarlets. The Ravens have won their last three RaboDirect PRO12 matches and have lost just once at Ravenhill in the competition all season.
Cuthbert is set to line up against fellow Lion Tommy Bowe as the Blues look to avenge the convincing 48-19 defeat to Ulster at Cardiff Arms Park earlier this season.
"Now the hamstring is good, I'm looking forward to getting back out there," said Cuthbert.
"Tommy's coming back from his own hamstring injury and we all know about him. He's definitely got the most experience of us.
"Coming up against Tommy this weekend will be good fun."