Final Table hand Stars 100k

[Zimmer4141]

PokerStars Game #10279222389: Tournament #51769630, $150+$12 Hold'em No Limit - Level XXII (6000/12000) - 2007/06/05 - 02:57:24 (ET)
Table '51769630 6' 9-max Seat #6 is the button
Seat 2: Bella-GG (546935 in chips)
Seat 3: Joao M. (224928 in chips)
Seat 4: Zimmy41 (657530 in chips)
Seat 5: xxCelticFCxx (338737 in chips)
Seat 6: g0lfa (159870 in chips)
Bella-GG: posts the ante 600
Joao M.: posts the ante 600
Zimmy41: posts the ante 600
xxCelticFCxx: posts the ante 600
g0lfa: posts the ante 600
Bella-GG: posts small blind 6000
Joao M.: posts big blind 12000
*** HOLE CARDS ***
Dealt to Zimmy41: [As Ks]
Zimmy41: raises 20400 to 32400
xxCelticFCxx: raises 305737 to 338137 and is all-in
g0lfa: folds
Bella-GG: folds
Joao M.: calls 212328 and is all-in
Zimmy41 ??????

So far Celtic had been the only guy to come over the top of me, and he had begun to do so more often over the past few rounds. Joao is a very good player and I would give him a tight range here. Is this a call or fold? (I'm playing for first obv and not to move up)