Seems that McLaren is just about to fire up its 2015 challenger for the first time.
Currently only Rosberg and Sainz out on track. Rosberg has improved to a 1:23.106, so that Mercedes is absolutely flying out there this morning already.
By way of comparison, last year's benchmark was 1:23.276. In 2013, Felipe Massa recorded a 1:17.879 so we're still a long way off the V8s.
@AnirudhVenkatesh: These cars are still in the middle of a development curve which started last year, so yes, naturally they will be getting quicker and quicker as the V6 era continues.
@Siddhesh: Still a way to go yet but yes, these cars are getting faster and faster.
@SaptakDas: Alonso. Poor old Magnussen won't be doing any testing and is unlikely to get much Friday practice during the season either.
Sainz returns to the pits but Vettel joins fellow countryman Rosberg out on track. It's just the two Germans out there for the time being.
@AnirudhVenkatesh: Saniz is in the Toro Rosso today. Verstappen will be in the car on Monday and Wednesday.
@Shadez058: In a word? Sexy!
It is worth noting Mercedes has ploughed straight into a long run early on this morning. Some ominous early signs for its rivals at the moment.
Worth remembering not everyone is testing today....
@SaptakDas: That's right. Force India is focusing on the Barcelona double header at the end of this month.
Rosberg has just completed his 20th lap of the morning. Vettel has clocked nine.
Rosberg and Vettel return to the pit lane and it's all quiet on the testing front.
For those of you asking about Alonso, our man Laurence is on the case. We should be seeing him shortly.
Ricciardo now out on track and moves into second with a 1:25.703 in that zebra car. That moves him above old team-mate Vettel but he's still 2.5s off Rosberg.
Worth noting Ricciardo is on the hard tyre, while Rosberg's benchmark has been set on the mediums. Ricciardo goes faster still, improving to a 1:25.131.
@Siddhesh: Those times are correct as of 1000. We will update shortly - unfortunately we do not have a live feed from Jerez as we do from races.
Alonso has his overalls on and looks about ready to get out on track.
Ericsson returns to the fray to join Ricciardo on track.
Ricciardo now returns to the pits, leaving Ericsson out there on his own. The Swede has just crossed in a 1:28.6.
@Prajesh: And there's zebras everywhere!
@JhonathanQuintino: No sign of Williams yet. The team unveiled its car this morning but is yet to join the track.
Ericsson improves his personal best to a 1:26.589.
@Nikola2411: Any minute now, we think!
Sainz Jr also out there on track with Ericsson.