This year's Indianapolis 500 will have at least 32 drivers contending to make the starting grid for the May 26 race, the 97th running of the famed 'greatest spectacle in motorsport. (See full entry list.)

With Opening Day coming up on Saturday, teams are heading to Indianapolis - many of them having to jet all the way back from Brazil after Sunday's thrilling Sao Paulo Indy 300 race - in order to be ready for a full week of practice before a weekend consisting of Pole Day and Bump Day qualifying efforts.

This year's line-up will consist of three past winners of the Indy 500 and four IZOD IndyCar Series champions. Dario Franchitti and Helio Castroneves are both three-time winners of the event and both are keen to match AJ Foyt, Al Under and Rick Mears in taking a fourth victory at the 2.5-mile speedway.

Castroneves has the most appearances in the Indy 500 of the current field of active drivers with 12 starts to his name, while Franchitti is the oldest competitor currently entered in the race - he'll turn 40 the week before.

Andretti Autosport's Carlos Munoz is the youngest driver listed at the age of 21, and he is one of four rookies entered in this year's event. Along with AJ Allmendinger (Penske), Conor Daly (AJ Foyt Racing) and Tristan Vautier (Schmidt-Peterson Motorport), Munoz will have to complete the mandatory Rookie Orientation Program at Indianapolis which this year has been organised in special two-hour slots on Saturday and Sunday.

In total there are 17 Chevrolet entries listed and 16 Honda-powered cars, making 33 in all together with a matching spare 'T' car in all cases making 66 cars altogether. One car - the #40/T Ed Carpenter Racing entry - does not yet have a driver nominated.

Former winners Buddy Lazier and Buddy Rice are two drivers expected to join the field in some capacity over the next couple of weeks, with Jaques Lazier also said to be looking for a race seat. English racer Jay Howard is said to be working on a late race deal, while compatriot Katherine Legge said last week that she hadn't given up hope of making the race either.

That means there is a decent prospect of more than 33 cars vying to make the starting grid of the race, which could restore 'Bump Day' to a time of nail-biting drama once again after a lacklustre time of it in 2012 in which all entrants were guaranteed a place on the starting grid - even those struggling with the significantly under-powered Lotus engine.

Last year's polewinner Ryan Briscoe will return to Ganassi Racing for this year's event, after several seasons spent competing with Team Penske. Pippa Mann was last confirmed as having a race seat at Dale Coyne Racing, while Michel Jourdain Jr. will return to competition with Rahal Letterman Lanigan for the second year in succession.

The latest addition to the entry list is Townsend Bell, who has been given a race seat by Panther Racing which has itself won two Indy 500 races in the past.

"We're happy to have Townsend back," said Panther Racing CEO and Managing Partner John Barnes said. "We feel like this addition really strengthens our effort with JR Hildebrand and Oriol Servi? as we prepare to make another run at the Indianapolis Motor Speedway."

Bell - who has been working as a co-commentator for the IZOD IndyCar Series television coverage on the NBC Sports Network in 2013 - will be sponsored by fuel suppliers Sunoco and by film studio DreamWorks. He'll take at the wheel of the #60 car for his bid to make his seventh start in the race having made his Indy 500 d?but in 2006. So far at Indianapolis, he's taken three top ten finishes with a best finish of fourth place in 2011

"I'm a lucky guy," Bell said. "To be able to return to a top team like Panther and at the same time join up with Sunoco and DreamWorks is a special occasion. Despite the late start, we're focused on making the most of the opportunity. With Panther's previous record at Indy I can't wait to get on track.

Pippa Mann's Dale Coyne Racing car has not yet announced its number, but the headline sponsor will be Cyclops Gear (a boutique line of recording eyewear) with further financial backing from Stenz Construction, Royal Spa and Bell Helmets. The associate sponsors will also make contributions to the Racing for Charity foundation.

"It's great to have been able to connect my associate sponsors with Racing For Cancer," said Mann. "It's a great opportunity to join this amazing organization in helping those afflicted with cancer and promoting early detection and prevention initiatives that support the global fight against cancer. I am extremely proud to be carrying the logo on my sleeve at this year's Indy 500."

Click here for the full 2013 Indy 500 entry list.