[article id="1640277"]Alicia Keys and Swizz Beats announced[/article] late Thursday evening that they're engaged, and that the Grammy-winning singer is expecting the couple's first child together.

The news might have been a surprise to some: Keys is an R&B/pop superstar who has performed at [article id="1603154"]President Barack Obama's inauguration[/article], while Swizz (real name: Kasseem Dean) is a Ruff Ryders alumnus and a veteran hip-hop producer who's laced Jay-Z and DMX with some of their grittiest tracks.

But the musical couple have been dating for a couple of years, at least since 2008, when rumors of their union began to swirl -- and recently whispers about the two ratcheted up when photos of Keys with what appeared to be a baby bump appeared online.

Here's a timeline of the couple's relationship:

» In 2008, music-industry insiders began buzzing about a pairing between Swizz -- then married to R&B chanteuse Mashonda -- and Keys, but the speculation turned public when gossip blog TheYBF.com published a post detailing their union, citing a source close to the singer.

» Later in 2008, Alicia Keys threw a surprise birthday party for the art-collecting producer (who by then was separated from his wife) at New York's Guggenheim Museum. Although they wouldn't appear in public together until the following year, the shindig solidified that the two were an item.

» In 2009, Swizz Beatz all but confirmed his relationship with Keys through a remix verse he added to Drake's hit, "Best I Ever Had," rapping, "She gave me a party at the Guggenheim ... What's next? The ring? The baby? She really loves me."

» Throughout the year, Keys and Swizz (engaged in a [article id="1589419"]messy divorce from Mashonda[/article], including public spat on Twitter) were spotted together at a bevy of events, including his pre-Grammy Awards event, game three of World Series (where she [article id="1625161"]performed alongside Jay-Z[/article]), and a swank Whitney Houston album preview event; the musical pair worked together to produce the [article id="1616755"]Houston single "Million Dollar Bill."[/article]

» This year, the duo have been frequently photographed together, both domestically and abroad; pics of Keys performing across the Atlantic caused a stir online as the singer's loose-fitting clothing led many to believe she was hiding a baby bump.

» On Thursday, a spokesperson for the couple confirmed that they were engaged and are expecting their first child together. The baby will be her first and his third: The producer has two other children from previous relationships.

What do you think about Swizz Beats and Alicia Keys' relationship? Let us know in the comments!