Dmitry Peskov, who is given a broad remit to voice the views of the Kremlin strongman, was photographed wearing the pricey timepiece as he tied the knot with Olympic ice dancer Tatiana Navka on Saturday in the Black Sea resort of Sochi.
As images of the glitzy event emerged, speculation centred on the striking black watch on Peskov's wrist, its face decorated with a gold skull.
Opposition politician and corruption whistleblower Alexei Navalny identified it as a limited edition watch designed by Richard Mille.
The watch is worth at least US$620,0000, he wrote on his blog, citing an e-mail written to him by the Swiss watchmakers.
"The bridegroom's watch cost more than your apartment," he titled his investigation.
Navalny published photographs of Peskov wearing other costly watches including a Rolex and an Omega.
Russian corruption busters have repeatedly focused on extremely expensive watches worn by officials who could hardly afford them on their declared salaries.
Peskov - who has an annual declared salary of some US$145,000 - brushed off speculation over the watch, saying it was a gift from his figure skater wife.
"Gifts from a wife to a husband or a husband to a wife can hardly have anything to do with anti-corruption activity," he told was quoted as saying by RIA Novosti state news agency.
Navka confirmed this, telling Komsomolskaya Pravda tabloid: "I can afford to give a good present." She said the cost of the watch had been exaggerated.
"Naturally, the price that everyone is discussing now, of course, does not correspond to reality." The wedding guests included a host of Russian pop stars and sports figures. But Putin himself was notably absent from photographs, although the couple earlier confirmed he was invited.
The details of the wedding cast a rare light on the way of life of the Kremlin's inner circle, with little sign of belt-tightening amid Russia's economic crisis.
Putin - with Peskov's help - has maintained a veil of secrecy over his own love life since he and his wife Lyudmila divorced.