Fans are counting down the days to this year's San Diego Comic-Con. All roads lead to SDCC Convention Center from July 18 to 21. We snooped around to find out which TV actors will show up for the fans this year. The biggest news is that "How I Met Your Mother" will be attending SDCC for the first time, with the original cast in complete attendance. Arrow, Once Upon a Time, Big Bang Theory, and Supernatural will also be there.

How I Met Your Mother - at the SDCC 2013? (There's a first time for everything!)

Josh Radnor, Cobie Smulders, Jason Segel, Neil Patrick Harris and Alyson Hannigan are joining the SDCC panel for the first time. Promoting the final season of How I Met Your Mother is bound to be a bittersweet journey for the cast and the CBS show's fans. The Hollywood Reporter notes the HIMYM folks will be showing up on July 20, Saturday. It would be fantastic if Cristin Milioti (the mother) could attend, too. Cristin, who showed up for the first time in HIMYM Season 8 finale, is the only regular cast to be added into the show.

Arrow Season 2: Who Gets to Suit Up First - Roy Harper or Black Canary?

Stephen Amell, Katie Cassidy, David Ramsey, Emily Bett Rickards and Colton Haynes will join The CW's Arrow showrunners Greg Berlanti, Marc Guggenheim and Andrew Kreisberg on the panel. Oliver Queen (Green Arrow) will soon be joined by Roy Harper and Black Canary on Arrow Season 2. You can bet a number of crazy girls will come as Black Canary in their cosplay number. The question is: Who will be the first to suit up with the Hood Guy - Katie or Colton?

Olicity shippers should not miss this cool event with the Arrow cast. THR reported the Arrow panellists will come out on July 20, too.

Once Upon a Time Season 3: Snow White, Emma Swan and Prince Charming Go to Neverland!

'Once Upon a Time' SDCC reps have yet to be named. But cast and producers will show up, according to THR. The last time we saw them, Snow White, Emma Swan and Prince Charming are all headed to Neverland to rescue Henry.

Meantime in the Enchanted Forest, Neal meets Sleeping Beauty, Prince Philip and Mulan. Who else will we seen in OUAT Season 3? Like HIMYM and Arrow, OUAT is scheduled to meet the fans on July 20.

'The Big Bang Theory' writers Steve Molaro and Bill Prady will attend, but hopes are not raised for the cast's attendance on July 19, Friday. (But Sheldon Cooper and friend live for comic-cons, right?)

'Bones' showrunners Hart Hanson and Stephen Nathan will also attend the SDCC 2013 with star David Boreanaz (Seeley Booth). They will be around on the same day as TBBT, July 19.

'Supernatural' stars Jared Padalecki, Jensen Ackles, and Misha Collins will also grace this year's comic-con. The gang's schedule falls on July 21, Sunday, the same day as 'Breaking Bad' and 'Sons of Anarchy.'

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