Henriques is set to bat at six and provide some extra options in Australia's bowling attack. Australia will be led by Michael Clarke in Chennai, while opening batsman David Warner will play despite his broken thumb having not yet fully healed.
Henriques stumbled over words when discussing his selection on Wednesday, having been told by coach Mickey Arthur on Tuesday night. "It's nice to know a couple of days out that you're playing and to know that you can go into training and really attack the plans and the methods that you're going to try and use in the game as well," Henriques said.
"I had a fair idea, once selected on the tour, before even coming to India, having played here before...what I might be up against and I've got some pretty clear plans. (But) obviously going out there and executing them is a different kettle of fish."
Henriques claims his previous experience in India (he played two one-day internationals there in 2009) should give him some confidence in Chennai but remains amazed at being picked.
"I was told last night," Henriques said. "Mickey came in and passed on the news to me and...yeah...I was obviously as lost for words as I am now."
The 26-year-old Portuguese-born all-rounder, who cites fellow New South Welshmen Steve and Mark Waugh as his boyhood heroes, tried to contact his parents on Tuesday but as yet has failed to tell them about his impending Test debut.
"I've tried but I haven't been able to get through," Henriques said.
"Obviously when I found out they were fast asleep and I tried calling earlier this morning and they're both at work, so I think they're going to be pretty shocked and very happy for me."
Team for first Test: M Clarke (c), E Cowan, M Henriques, P Hughes, N Lyon, J Pattinson, P Siddle, M Starc, M Wade, D Warner, S Watson.