Ireland head coach Joe Schmidt has hailed Brian O'Driscoll as a "phenomenal professional" ahead of the Irishman's 130th cap.
O'Driscoll will in the process equal the 139-cap record set by George Gregan, when adding his eight Test appearances for the British and Irish Lions onto his 130 for Ireland.
The 35-year-old is in his final season and ahead of reaching the landmark at Twickenham, Schmidt, who worked with O'Driscoll at Leinster, didn't hold back in his praise.
"To be honest I didn't play Test rugby so I wouldn't be the best to judge, because I would think one Test would be phenomenal," said Schmidt.
"Where I grew up in a black jersey it would have been phenomenal, so how you manage to amass 130 of them, I'm not quite sure how you do it.
"You have to be incredibly resilient, incredibly talented, a phenomenal professional, and there's your summary: that's Brian O'Driscoll.
"I think he's a very tough character, and the person he is allows him to be the player he's been, and hopefully the player he will be on Saturday at four o'clock."
Schmidt's Ireland face their first away game since the Kiwi took over the head coaching role last November, but given his squad are packed full of experience Schmidt has no concerns about how the Six Nations favourites will handle the occasion.
"Thankfully I've got a lot of players who've drawn on a lot of experiences at Twickenham itself in the Test arena," added Schmidt.
"We have very much a player-driven environment, they set the standard, I find them incredibly responsive when we're looking at strategy and what we need to deliver technically and tactically.
"But when it comes to directing and controlling the group it doesn't need to be about what experiences I've had, or what I need to bring to the table.
"It's very much their experiences, and there is a good core of experienced players there, so they can lead that and give the younger players the confidence that they've been here before, they know what it takes and they're ready to roll their sleeves up and live with that."